Of course, the glue that holds the entire application together is the IPN class. I had previously used the freely-available IPN class from XDev Software. Note that this class is designed for regular PayPal transactions. I had to customize it to handle PayPal subscriptions.

ASP.NET code & controls to handle submitting single payments, subscriptions & payments to PayPal standard.

If you've pulled your hair out trying to implement any sort of plausible solution to Google Checkout and PayPal integration, check out this amazingly simple solution!

Those who create commercial sites are faced with the question, "How should it receive payments?" One of the most popular payment systems in the world is PayPal. This system is often chosen because it is reliable, simple to use and allows an account to be easily opened. To open an account, ...