You can do reasonably well (if you're just after pocket change) with a decent utility app - let's be honest, most of them have shockingly bad UX, and reap ad revenue.

It's a utility app. I think that if you build something people will get some use out of, and make it look (and be) easy to use then you should get a fairly recurring revenue. A lot of the smaller apps look bad, so i just tried to make mine look a little more like something i'd want to use.

I think it depends on store positioning too, once i got into the top charts for my section then I got more downloads (or maybe i got there because i got more downloads, i guess it's a rolling ball effect).

I plan to do some more utility ones soon, and i'm working on a bit of a bigger one (health based) now that will hopefully provide more value to people.

I'd be happy to tell you more about it and what i did if you want. My email is in my profile.