I've created my own website that sells user-generated content. Since it's not a typical storefront (merchandise is constantly being added by the users), I developed it myself. Now I'm looking for a shopping cart that can take care of the payment for me. Since I'm selling content, I don't care about quantity, shipping, taxes, etc. I just want to say "pay $x on product y" (which it doesn't need to correlate with any databases) and then take care of the payment, and return that product y was paid for. Once I get that product y was paid for, I can unlock it (hence no need to worry about shipping).

Any suggestions? Thanks.