Hi!

I was wondering if anyone could point me out to a credit card accepting
service that I can integrate into my website cheaply.

Basically, I have a user send a file to my server, which analyzes it
for the price, then allows the user to purchase a "key" in order to
unlock the file for their use.  After they buy the rights to the file,
they are redirected to a page that generates the key and allows them to
download the file.

I could use any advice that anyone would like to give me/  Thanks