Did some searching, found a few threads pointing to some add-ons. I'm still a little confused.

This is what I want to do. I want to have a normal shopping cart, where they add things to the cart and checkout, then they can download the file they paid for, for life.

Then I want a way that they can just buy a membership and get access to every file download as long as they are a member.

Does anybody have experience with this?