I'm creating a fake account right now for test purposes and apparently you can sell stuff for $0. You can easily test it without actually doing anything "real".

As a seller my only issue is the sales link has a Gumroad logo that is kind of big and would be better listed as "powered by Gumroad" instead of just Gumroad as not to confuse users, but I have a feeling that will be a premium feature :)

The rest of the product is extremely simple to use.