Hi, I use Electroneum and Phoneum apps. Any of them use your mobile resources.
Electroneum: Recently I received the first Electroneum paid (100ETN). You only need open the app once a week.
Phoneum: Similar app. And you can earn some bonus coins whit some games (optional). Whit phoneum you can even trade in some exchange.
In my personal opinion I prefer electroneum, but both can be worthy