Do you know Mobeleader?
I as mobile marketing network which work ads in-App and where developers can make their Apps profitable.
They have free libraries like:
- NickCenter: a library that allows to integrate a registration system in order to create an users data base, communicate with users by mail or push notifications and offer to registered users an Freemium App where they will be able to surfer the app without visualizing ads in-App.
That is possible because Mobeleader will pay for valid registers. (It is available for iOS Apps and shortly for Android).
- Push Library: developers can make an unlimited and free use of it.