I would pay 20 bucks for an app that costs 20 bucks! But on a serious note, maybe an Android Launcher replacement with a simplistic UI that brings character to the table. Go Launcher EX is nice, and Themer is nice too for changing the look.
I like the idea of this thread
Hmm, I would $20 for an app that would keep a PIN password on my phone when of knew I wasn't using it. If someone else picked it up, it would stay locked