nsoftware ibiz paypal direct payment module

I looked at the source code for the asp classic and it seemed simple enough, spent many hours struggling to learn all about paypal's sandbox, and now I have found out that I need to use asp.net instead of classic.

Does anyone have a simple sample of an aspx file that can work simply to process a payment?

We are providing 1,2, or 3 year subscriptions to an online service.

Could I rewrite the classic asp inside an aspx document?

Thanks for all your suggestions.