What is the best practice for unlocking app features to the user in Android?

Question

I just developed an Android App which I´d like to distribute for free.

In order to be able to earn some money for my work, I´d like to add some adverts or notificati

Answer 1

You can do this through the Android Marketplace with in-app billing. There are also a lot of apps that offer a free version and a paid version, where the paid version has more features or fewer ads.