Gumroad

With Gumroad, anyone can earn their first dollar online. Just start with what you know, see what sticks, and get paid. It's that easy.

You know all those great ideas you have? We want you to try them, lots of them, and find out what works.

The team behind the super successful site has fully open-sourced their largely Ruby on Rails codebase for anyone to run their own version.

Nate Berkopec has a wonderful video walkthru of some of the interesting pieces of code.

Note: it is rail.market's recommendation that you use this project only for reference and learning, due to licensing restrictions.