I originally sold my app on Beyond.com (which was originally software.net). They took 10% which didn't seem too bad. One day they contacted me about giving my app a "freebate" -- basically the app was still $29.95 but buyers could fill out a form and send it in and eventually (like months later) get their $29.95 back. Per their data only about half of buyers ever bothered to do this so it was effectively a 50% off deal. Beyond.com was supposed to give me about $10 per copy sold instead of the normal $27 to cover the freebate and they would make $5 per copy instead of their normal $3.

I said OK and they featured my app on their front page and sales went up like 100X and I was of course pretty happy. The funny part was that their accounting system was all fucked up and I kept getting $27 per copy sold even though the freebate was still in place. I actually tried contacting them multiple times about this to get the situation corrected and I could never get through to anybody who had any clue about what was going on. Eventually they went bankrupt and shut down and years later I got one of those class-action settlement checks in the mail without any explanation of what it was for. Maybe sales of my app were even better than they were telling me, I dunno. I've never once met a person in the real world who has ever even heard of the app so that doesn't seem very likely.