There seem to be three options:
- Charge for the app
- Put ads on the app
- Ask for donations
But I think people are both lazy and not evil. I think, I hope, that if I were to charge 99p for an app, it's not worth their while to go and download the source, compile, etc. Hopefully at least some of them will do it purely to support my work. Likewise, and possibly even more so, with ads (though I hate ads, as a general rule): hacking into the code to remove the ads won't be easy for non-programmers. I wonder if the source of the ad hooks will even be open-sourcable... it might have private information in it (though I would think that's unlikely).
Anyway, this is just me thinking out loud. All thoughts gratefully received.