I've come to the conclusion that donation apps don't work. So maybe I'll try adware.
Hope this doesn't alienate anybody... the thing still works - it'll still make it look like you're getting a call :-) The ads are on the first screen of the app, which doesn't do anything anyway. So what more logical place to put them.
Speaking of adware, the service that I'm using is Admob (www.admob.com). Works really well, nice website w/great reporting functionality. The ads are a bit meh once in a while but they're good the other 99% of the time.