Simplest E-Commerce: Help me please ! :)

So many E-Commerce plugins, they’re all over-qualified for my needs.

What I need:
* E-Commerce site that doesn’t have products.
* 1 empty box for customers to fill in the number of $$ they want to pay.
* Credit option is a must. Paypal option is a plus.
* should still have fields like “Email” “Name” “User_Name” etc.
* automated receipt to email.
* option to send a “follow-up” Email when the product has been delivered

Basically, imagine this site is selling only 1 (virtual) product. the customer choose how much money they want to pay for it. They fill a form, and in it they write their amount. no fixed price.
Everything else should be like a normal E-Commerce site.

I’m Extremely new to WP, but already went through the more popular plugins in that category.
Surely I’m missing something, please point me in the right direction.

Thanks a million!! ??

[ No bumping please. ]