Canonical Announces Ubuntu App Showdown
alphadogg writes "Linux developers will soon have a chance to compete for prizes of laptops and smartphones, thanks to Canonical's announcement this week of the Ubuntu App Showdown contest. Developers will have from June 18 until July 9 — a total of three weeks — to create an app using Canonical's Quickly development tool, which combines Python and GTK into a single Ubuntu-centric package. The resulting apps will be judged by a five-member panel, with the developers of the top three receiving new Nokia N9 smartphones."
http://developer.ubuntu.com/2012/06/ubuntu-app-showdown-no-longer-requires-quickly/
You can sell apps on the Ubuntu Software Center and have been able to for some time.