Google/Android Apps Privacy Policy

The billing Apps have no access to your private data.
They do utilise your bill data, if you have saved it [and I recommend that you do]. Bill data goes no further than the in App calculations.
The media Apps need functional access to the Internet and to memory; the Maker needs contact data but only if you copy an email address. Neither are collecting or using data for nefarious purposes.

The Paid Apps make use of the Android License Checking Library, to check that you have paid for the App. This data is not actually available to the App (other than an indication of the result) and is in any case encrypted.

So in the words of The Hitch-hiker's Guide to the Galaxy; "Don't Panic".