I’d like to expand a little bit on my previous response because I know
how difficult this might be going forward for you. I’d like to help you
out as much as I can.
So, inevitably you are going to have to think about how everything will
function. Personally, when I envisioned my cart, I read and watched all
the screencasts related to the subject and then diagramed the following:
A Stores Controller
– this would work as the controller for the shopping cart
– houses an Add to Cart method
– houses a checkout method
A Products Controller and Model
– would house the products or services we sell
A Order Model
– This would house the orders
A Payment Notifications Controller
– This would process incoming IPN notifications
I’m not sure how much you’ve worked out thus far, but you will need to
read and watch the screencasts, gain an idea about what you want to do
and implement, piece it out first, and then start slowly.
I would work out your products first, then your stores controller. You
will have the ability to add and manipulate the products in your cart
with those two pieces.
Once you master that and how you want to handle the sessions for the
cart, you can then implement an orders model and a payment notifications
system to handle the gateway transactions.
The idea here is to take baby steps into the process until it becomes
clearer to you.