I sold my Android app on Apptopia and it was really a great experience. I spent 6 weeks developing a really nice, 100% original Android game that I thought was great. I had some IAP and an ad or two, but I never made more than $10 from the game. Nonetheless, I had 10k+ downloads and it was certainly a high-quality effort. I thought (and still think) that there was money to be made from the game I just didn't have time to execute. I listen on Apptopia with a high price of $2500, being totally honest about my ~$0 revenue so far. A few months later, I had an offer and my app was sold. The process was easy and I'd recommend it to anyone with a side project they don't have time to maintain. Also I'd like to personally vouch for Apptopia's founder, Jon. I have been in email contact with him since the early days of the website and he will work incredibly hard to sell your app if you list it. He personally found my buyer for me and made the deal happen.