Maybe
ShareIt.com or
Plimus.com? I think Plimus charges 10% of your sale price in the $10 to $50 range. ShareIt lets you choose between either $3 + 5% or a straight %15 fee. They seem pretty similar in how they work - they display some info about your software product and handle the download and billing. Then the author does the rest including sending the license key and handling support.
I've bought a couple of things on ShareIt and so have the impression that more independent-type, niche products are sold through ShareIt.
take care-
Paul