Hello I have a question about making money on android apps. On app store we can find so many pay application and It's easy to now how they make money. The have profits from charges. In google play we have some pay apps but a lot is for free. Could someone tell me how they make money? I'm not talking about AdSense, do you now some other examples? I few months ago I have seen TV program where they talk about date collected from users. Something like cookies, is it possible to make money on it? Unfortunately I just watch that TV program for a few minutes. From another hand, when I agree to give permission app to see my contact, pictures, GPS, WIFI etc. they can sell it to 3 part company (media houses etc.) ? May be you now something about it, you now some great articles or books about making money on free apps ? ? ? Thanks in advance!