diff --git a/common/lib/xmodule/xmodule/course_module.py b/common/lib/xmodule/xmodule/course_module.py
index 57b13c10b3..caf731a392 100644
--- a/common/lib/xmodule/xmodule/course_module.py
+++ b/common/lib/xmodule/xmodule/course_module.py
@@ -338,6 +338,7 @@ class CourseFields(object):
     show_timezone = Boolean(help="True if timezones should be shown on dates in the courseware", scope=Scope.settings, default=True)
     enrollment_domain = String(help="External login method associated with user accounts allowed to register in course",
                         scope=Scope.settings)
+    enrollment_cost = Dict(scope=Scope.settings, default={'currency':'usd', 'cost':0})
 
     # An extra property is used rather than the wiki_slug/number because
     # there are courses that change the number for different runs. This allows
diff --git a/common/static/js/capa/spec/jsinput_spec.js b/common/static/js/capa/spec/jsinput_spec.js
deleted file mode 100644
index a4a4f6e57d..0000000000
--- a/common/static/js/capa/spec/jsinput_spec.js
+++ /dev/null
@@ -1,70 +0,0 @@
-xdescribe("A jsinput has:", function () {
-
-    beforeEach(function () {
-        $('#fixture').remove();
-        $.ajax({
-            async: false,
-            url: 'mainfixture.html',
-            success: function(data) {
-                $('body').append($(data));
-            }
-        });
-    });
-
-
-
-    describe("The jsinput constructor", function(){
-
-        var iframe1 = $(document).find('iframe')[0];
-
-        var testJsElem = jsinputConstructor({
-            id: 1,
-            elem: iframe1,
-            passive: false
-        });
-
-        it("Returns an object", function(){
-            expect(typeof(testJsElem)).toEqual('object');
-        });
-
-        it("Adds the object to the jsinput array", function() {
-            expect(jsinput.exists(1)).toBe(true);
-        });
-
-        describe("The returned object", function() {
-
-            it("Has a public 'update' method", function(){
-                expect(testJsElem.update).toBeDefined();  
-            });
-
-            it("Returns an 'update' that is idempotent", function(){
-                var orig = testJsElem.update();
-                for (var i = 0; i++; i < 5) {
-                    expect(testJsElem.update()).toEqual(orig);
-                }
-            });
-
-            it("Changes the parent's inputfield", function() {
-                testJsElem.update();
-              
-            });
-        });
-    });
-
-
-    describe("The walkDOM functions", function() {
-
-        walkDOM();
-
-        it("Creates (at least) one object per iframe", function() {
-            jsinput.arr.length >= 2; 
-        });
-
-        it("Does not create multiple objects with the same id", function() {
-            while (jsinput.arr.length > 0) {
-                var elem = jsinput.arr.pop();
-                expect(jsinput.exists(elem.id)).toBe(false);
-            }
-        });
-    });
-})
diff --git a/lms/djangoapps/shoppingcart/models.py b/lms/djangoapps/shoppingcart/models.py
index 052ecfb888..acc0545ab7 100644
--- a/lms/djangoapps/shoppingcart/models.py
+++ b/lms/djangoapps/shoppingcart/models.py
@@ -123,11 +123,13 @@ class OrderItem(models.Model):
 
         Unfortunately the QuerySet used determines the class to be OrderItem, and not its most specific
         subclasses.  That means this parent class implementation of purchased_callback needs to act as
-        a dispatcher to call the callback the proper subclasses, and as such it needs to know about all subclasses.
-        So please add
+        a dispatcher to call the callback the proper subclasses, and as such it needs to know about all
+        possible subclasses.
+        So keep ORDER_ITEM_SUBTYPES up-to-date
         """
-        for classname, lc_classname in ORDER_ITEM_SUBTYPES:
+        for cls, lc_classname in ORDER_ITEM_SUBTYPES.iteritems():
             try:
+                #Uses https://docs.djangoproject.com/en/1.4/topics/db/models/#multi-table-inheritance to test subclass
                 sub_instance = getattr(self,lc_classname)
                 sub_instance.purchased_callback()
             except (ObjectDoesNotExist, AttributeError):
@@ -135,13 +137,18 @@ class OrderItem(models.Model):
                               .format(lc_classname))
                 pass
 
-# Each entry is a tuple of ('ModelName', 'lower_case_model_name')
-# See https://docs.djangoproject.com/en/1.4/topics/db/models/#multi-table-inheritance for
-# PLEASE KEEP THIS LIST UP_TO_DATE WITH THE SUBCLASSES OF OrderItem
-ORDER_ITEM_SUBTYPES = [
-    ('PaidCourseRegistration', 'paidcourseregistration')
-]
-
+    def is_of_subtype(self, cls):
+        """
+        Checks if self is also a type of cls, in addition to being an OrderItem
+        Uses https://docs.djangoproject.com/en/1.4/topics/db/models/#multi-table-inheritance to test for subclass
+        """
+        if cls not in ORDER_ITEM_SUBTYPES:
+            return False
+        try:
+            getattr(self, ORDER_ITEM_SUBTYPES[cls])
+            return True
+        except (ObjectDoesNotExist, AttributeError):
+            return False
 
 
 class PaidCourseRegistration(OrderItem):
@@ -151,7 +158,16 @@ class PaidCourseRegistration(OrderItem):
     course_id = models.CharField(max_length=128, db_index=True)
 
     @classmethod
-    def add_to_order(cls, order, course_id, cost, currency='usd'):
+    def part_of_order(cls, order, course_id):
+        """
+        Is the course defined by course_id in the order?
+        """
+        return course_id in [item.paidcourseregistration.course_id
+                             for item in order.orderitem_set.all()
+                             if item.is_of_subtype(PaidCourseRegistration)]
+
+    @classmethod
+    def add_to_order(cls, order, course_id, cost=None, currency=None):
         """
         A standardized way to create these objects, with sensible defaults filled in.
         Will update the cost if called on an order that already carries the course.
@@ -164,6 +180,10 @@ class PaidCourseRegistration(OrderItem):
         item, created = cls.objects.get_or_create(order=order, user=order.user, course_id=course_id)
         item.status = order.status
         item.qty = 1
+        if cost is None:
+            cost = course.enrollment_cost['cost']
+        if currency is None:
+            currency = course.enrollment_cost['currency']
         item.unit_cost = cost
         item.line_cost = cost
         item.line_desc = 'Registration for Course: {0}'.format(get_course_about_section(course, "title"))
@@ -182,9 +202,6 @@ class PaidCourseRegistration(OrderItem):
                                                  # throw errors if it doesn't
         # use get_or_create here to gracefully handle case where the user is already enrolled in the course, for
         # whatever reason.
-        # Don't really need to create CourseEnrollmentAllowed object, but doing it for bookkeeping and consistency
-        # with rest of codebase.
-        CourseEnrollmentAllowed.objects.get_or_create(email=self.user.email, course_id=self.course_id, auto_enroll=True)
         CourseEnrollment.objects.get_or_create(user=self.user, course_id=self.course_id)
 
         log.info("Enrolled {0} in paid course {1}, paid ${2}".format(self.user.email, self.course_id, self.line_cost))
@@ -193,3 +210,11 @@ class PaidCourseRegistration(OrderItem):
                          tags=["org:{0}".format(org),
                                "course:{0}".format(course_num),
                                "run:{0}".format(run)])
+
+
+# Each entry is a dictionary of ModelName: 'lower_case_model_name'
+# See https://docs.djangoproject.com/en/1.4/topics/db/models/#multi-table-inheritance for
+# PLEASE KEEP THIS LIST UP_TO_DATE WITH THE SUBCLASSES OF OrderItem
+ORDER_ITEM_SUBTYPES = {
+    PaidCourseRegistration: 'paidcourseregistration',
+}
\ No newline at end of file
diff --git a/lms/djangoapps/shoppingcart/processors/CyberSource.py b/lms/djangoapps/shoppingcart/processors/CyberSource.py
index 17e1511ac6..75ad754237 100644
--- a/lms/djangoapps/shoppingcart/processors/CyberSource.py
+++ b/lms/djangoapps/shoppingcart/processors/CyberSource.py
@@ -13,7 +13,7 @@ from django.conf import settings
 from django.utils.translation import ugettext as _
 from mitxmako.shortcuts import render_to_string
 from shoppingcart.models import Order
-from .exceptions import CCProcessorDataException, CCProcessorWrongAmountException
+from .exceptions import CCProcessorException, CCProcessorDataException, CCProcessorWrongAmountException
 
 shared_secret = settings.CC_PROCESSOR['CyberSource'].get('SHARED_SECRET','')
 merchant_id = settings.CC_PROCESSOR['CyberSource'].get('MERCHANT_ID','')
@@ -21,6 +21,42 @@ serial_number = settings.CC_PROCESSOR['CyberSource'].get('SERIAL_NUMBER','')
 orderPage_version = settings.CC_PROCESSOR['CyberSource'].get('ORDERPAGE_VERSION','7')
 purchase_endpoint = settings.CC_PROCESSOR['CyberSource'].get('PURCHASE_ENDPOINT','')
 
+def process_postpay_callback(request):
+    """
+    The top level call to this module, basically
+    This function is handed the callback request after the customer has entered the CC info and clicked "buy"
+    on the external Hosted Order Page.
+    It is expected to verify the callback and determine if the payment was successful.
+    It returns {'success':bool, 'order':Order, 'error_html':str}
+    If successful this function must have the side effect of marking the order purchased and calling the
+    purchased_callbacks of the cart items.
+    If unsuccessful this function should not have those side effects but should try to figure out why and
+    return a helpful-enough error message in error_html.
+    """
+    params = request.POST.dict()
+    if verify_signatures(params):
+        try:
+            result = payment_accepted(params)
+            if result['accepted']:
+                # SUCCESS CASE first, rest are some sort of oddity
+                record_purchase(params, result['order'])
+                return {'success': True,
+                        'order': result['order'],
+                        'error_html': ''}
+            else:
+                return {'success': False,
+                        'order': result['order'],
+                        'error_html': get_processor_error_html(params)}
+        except CCProcessorException as e:
+            return {'success': False,
+                    'order': None, #due to exception we may not have the order
+                    'error_html': get_exception_html(params, e)}
+    else:
+        return {'success': False,
+                'order': None,
+                'error_html': get_signature_error_html(params)}
+
+
 def hash(value):
     """
     Performs the base64(HMAC_SHA1(key, value)) used by CyberSource Hosted Order Page
@@ -48,7 +84,7 @@ def sign(params):
     return params
 
 
-def verify(params):
+def verify_signatures(params):
     """
     Verify the signatures accompanying the POST back from Cybersource Hosted Order Page
     """
@@ -161,6 +197,18 @@ def record_purchase(params, order):
         processor_reply_dump=json.dumps(params)
     )
 
+def get_processor_error_html(params):
+    """Have to parse through the error codes for all the other cases"""
+    return "<p>ERROR!</p>"
+
+def get_exception_html(params, exp):
+    """Return error HTML associated with exception"""
+    return "<p>EXCEPTION!</p>"
+
+def get_signature_error_html(params):
+    """Return error HTML associated with signature failure"""
+    return "<p>EXCEPTION!</p>"
+
 
 CARDTYPE_MAP = defaultdict(lambda:"UNKNOWN")
 CARDTYPE_MAP.update(
diff --git a/lms/djangoapps/shoppingcart/processors/__init__.py b/lms/djangoapps/shoppingcart/processors/__init__.py
index 520c353535..45a6e3114d 100644
--- a/lms/djangoapps/shoppingcart/processors/__init__.py
+++ b/lms/djangoapps/shoppingcart/processors/__init__.py
@@ -8,8 +8,32 @@ module = __import__('shoppingcart.processors.' + processor_name,
                               'render_purchase_form_html'
                               'payment_accepted',
                               'record_purchase',
+                              'process_postpay_callback',
                               ])
 
+def render_purchase_form_html(*args, **kwargs):
+    """
+    The top level call to this module to begin the purchase.
+    Given a shopping cart,
+    Renders the HTML form for display on user's browser, which POSTS to Hosted Processors
+    Returns the HTML as a string
+    """
+    return module.render_purchase_form_html(*args, **kwargs)
+
+def process_postpay_callback(*args, **kwargs):
+    """
+    The top level call to this module after the purchase.
+    This function is handed the callback request after the customer has entered the CC info and clicked "buy"
+    on the external payment page.
+    It is expected to verify the callback and determine if the payment was successful.
+    It returns {'success':bool, 'order':Order, 'error_html':str}
+    If successful this function must have the side effect of marking the order purchased and calling the
+    purchased_callbacks of the cart items.
+    If unsuccessful this function should not have those side effects but should try to figure out why and
+    return a helpful-enough error message in error_html.
+    """
+    return module.process_postpay_callback(*args, **kwargs)
+
 def sign(*args, **kwargs):
     """
     Given a dict (or OrderedDict) of parameters to send to the
@@ -30,14 +54,6 @@ def verify(*args, **kwargs):
     """
     return module.sign(*args, **kwargs)
 
-def render_purchase_form_html(*args, **kwargs):
-    """
-    Given a shopping cart,
-    Renders the HTML form for display on user's browser, which POSTS to Hosted Processors
-    Returns the HTML as a string
-    """
-    return module.render_purchase_form_html(*args, **kwargs)
-
 def payment_accepted(*args, **kwargs):
     """
     Given params returned by the CC processor, check that processor has accepted the payment
diff --git a/lms/djangoapps/shoppingcart/processors/exceptions.py b/lms/djangoapps/shoppingcart/processors/exceptions.py
index bc132a3d54..e863688133 100644
--- a/lms/djangoapps/shoppingcart/processors/exceptions.py
+++ b/lms/djangoapps/shoppingcart/processors/exceptions.py
@@ -7,5 +7,5 @@ class CCProcessorException(PaymentException):
 class CCProcessorDataException(CCProcessorException):
     pass
 
-class CCProcessorWrongAmountException(PaymentException):
+class CCProcessorWrongAmountException(CCProcessorException):
     pass
\ No newline at end of file
diff --git a/lms/djangoapps/shoppingcart/urls.py b/lms/djangoapps/shoppingcart/urls.py
index 58e51f0b40..892c66d5bb 100644
--- a/lms/djangoapps/shoppingcart/urls.py
+++ b/lms/djangoapps/shoppingcart/urls.py
@@ -6,7 +6,6 @@ urlpatterns = patterns('shoppingcart.views',  # nopep8
     url(r'^add/course/(?P<course_id>[^/]+/[^/]+/[^/]+)/$','add_course_to_cart'),
     url(r'^clear/$','clear_cart'),
     url(r'^remove_item/$', 'remove_item'),
-    url(r'^purchased/$', 'purchased'),
-    url(r'^postpay_accept_callback/$', 'postpay_accept_callback'),
+    url(r'^postpay_callback/$', 'postpay_callback'), #Both the ~accept and ~reject callback pages are handled here
     url(r'^receipt/(?P<ordernum>[0-9]*)/$', 'show_receipt'),
 )
\ No newline at end of file
diff --git a/lms/djangoapps/shoppingcart/views.py b/lms/djangoapps/shoppingcart/views.py
index f5540aafbb..87df7eaf1b 100644
--- a/lms/djangoapps/shoppingcart/views.py
+++ b/lms/djangoapps/shoppingcart/views.py
@@ -1,13 +1,14 @@
 import logging
-
-from django.http import HttpResponse, HttpResponseRedirect, Http404
+from django.http import HttpResponse, HttpResponseRedirect, HttpResponseNotFound, HttpResponseForbidden, Http404
+from django.utils.translation import ugettext as _
 from django.core.urlresolvers import reverse
 from django.views.decorators.csrf import csrf_exempt
 from django.contrib.auth.decorators import login_required
+from student.models import CourseEnrollment
+from xmodule.modulestore.exceptions import ItemNotFoundError
 from mitxmako.shortcuts import render_to_response
 from .models import *
-from .processors import verify, payment_accepted, render_purchase_form_html, record_purchase
-from .processors.exceptions import CCProcessorDataException, CCProcessorWrongAmountException
+from .processors import process_postpay_callback, render_purchase_form_html
 
 log = logging.getLogger("shoppingcart")
 
@@ -16,20 +17,22 @@ def test(request, course_id):
     item1.purchased_callback(request.user.id)
     return HttpResponse('OK')
 
-@login_required
-def purchased(request):
-    #verify() -- signatures, total cost match up, etc.  Need error handling code (
-    # If verify fails probaly need to display a contact email/number)
-    cart = Order.get_cart_for_user(request.user)
-    cart.purchase()
-    return HttpResponseRedirect('/')
 
-@login_required
 def add_course_to_cart(request, course_id):
+    if not request.user.is_authenticated():
+        return HttpResponseForbidden(_('You must be logged-in to add to a shopping cart'))
     cart = Order.get_cart_for_user(request.user)
-    # TODO: Catch 500 here for course that does not exist, period
-    PaidCourseRegistration.add_to_order(cart, course_id, 200)
-    return HttpResponse("Added")
+    if PaidCourseRegistration.part_of_order(cart, course_id):
+        return HttpResponseNotFound(_('The course {0} is already in your cart.'.format(course_id)))
+    if CourseEnrollment.objects.filter(user=request.user, course_id=course_id).exists():
+        return HttpResponseNotFound(_('You are already registered in course {0}.'.format(course_id)))
+    try:
+        PaidCourseRegistration.add_to_order(cart, course_id)
+    except ItemNotFoundError:
+        return HttpResponseNotFound(_('The course you requested does not exist.'))
+    if request.method == 'GET':
+        return HttpResponseRedirect(reverse('shoppingcart.views.show_cart'))
+    return HttpResponse(_("Course added to cart."))
 
 @login_required
 def show_cart(request):
@@ -62,31 +65,23 @@ def remove_item(request):
     return HttpResponse('OK')
 
 @csrf_exempt
-def postpay_accept_callback(request):
+def postpay_callback(request):
     """
-    Receives the POST-back from processor and performs the validation and displays a receipt
-    and does some other stuff
-
-    HANDLES THE ACCEPT AND REVIEW CASES
+    Receives the POST-back from processor.
+    Mainly this calls the processor-specific code to check if the payment was accepted, and to record the order
+    if it was, and to generate an error page.
+    If successful this function should have the side effect of changing the "cart" into a full "order" in the DB.
+    The cart can then render a success page which links to receipt pages.
+    If unsuccessful the order will be left untouched and HTML messages giving more detailed error info will be
+    returned.
     """
-    # TODO: Templates and logic for all error cases and the REVIEW CASE
-    params = request.POST.dict()
-    if verify(params):
-        try:
-            result = payment_accepted(params)
-            if result['accepted']:
-                # ACCEPTED CASE first
-                record_purchase(params, result['order'])
-                #render_receipt
-                return HttpResponseRedirect(reverse('shoppingcart.views.show_receipt', args=[result['order'].id]))
-            else:
-                return HttpResponse("CC Processor has not accepted the payment.")
-        except CCProcessorWrongAmountException:
-            return HttpResponse("Charged the wrong amount, contact our user support")
-        except CCProcessorDataException:
-            return HttpResponse("Exception: the processor returned invalid data")
+    result = process_postpay_callback(request)
+    if result['success']:
+        return HttpResponseRedirect(reverse('shoppingcart.views.show_receipt', args=[result['order'].id]))
     else:
-        return HttpResponse("There has been a communication problem blah blah. Not Validated")
+        return render_to_response('shoppingcart.processor_error.html', {'order':result['order'],
+                                                                        'error_html': result['error_html']})
+
 
 def show_receipt(request, ordernum):
     """
@@ -107,7 +102,7 @@ def show_receipt(request, ordernum):
                                                             'order_items': order_items,
                                                             'any_refunds': any_refunds})
 
-def show_orders(request):
+#def show_orders(request):
     """
     Displays all orders of a user
     """
diff --git a/lms/templates/courseware/course_about.html b/lms/templates/courseware/course_about.html
index e4a453133d..4d22e6959c 100644
--- a/lms/templates/courseware/course_about.html
+++ b/lms/templates/courseware/course_about.html
@@ -59,7 +59,6 @@
 
     %endif
 
-
   })(this)
   </script>
 
@@ -93,6 +92,7 @@
                     <strong>${_("View Courseware")}</strong>
                     </a>
                 %endif
+
         %else:
             <a href="#" class="register">${_("Register for {course.display_number_with_default}").format(course=course) | h}</a>
 
diff --git a/lms/templates/shoppingcart/list.html b/lms/templates/shoppingcart/list.html
index 677077ba2d..0754cac311 100644
--- a/lms/templates/shoppingcart/list.html
+++ b/lms/templates/shoppingcart/list.html
@@ -25,7 +25,7 @@
 
             </tbody>
         </table>
-
+        <!-- <input id="back_input" type="submit" value="Return" /> -->
         ${form_html}
     % else:
         <p>${_("You have selected no items for purchase.")}</p>
@@ -44,6 +44,10 @@
                         location.reload(true);
                     });
         });
+
+        $('#back_input').click(function(){
+           history.back();
+        });
     });
 </script>
 
diff --git a/lms/templates/shoppingcart/receipt.html b/lms/templates/shoppingcart/receipt.html
index 01de3b3f83..0386b6b353 100644
--- a/lms/templates/shoppingcart/receipt.html
+++ b/lms/templates/shoppingcart/receipt.html
@@ -6,7 +6,11 @@
 
 <%block name="title"><title>${_("Receipt for Order")} ${order.id}</title></%block>
 
-
+% if notification is not UNDEFINED:
+<section class="notification">
+    ${notification}
+</section>
+% endif
 
 <section class="container cart-list">
     <p><h1>${_(settings.PLATFORM_NAME + " (" + settings.SITE_NAME + ")" + " Electronic Receipt")}</h1></p>