Android - How to disable in-app purchases
You can't disable in-app purchases on Android phones as it is the case for iOS devices, but still you can lock these features with a PIN (which will be required for each of your purchases).
- Open the Google Play App.
- Press your phone's Menu button and go to Settings.
- Scroll to the "User Controls" section.
- Tap on "Set or Change PIN option" and enter a 4 digit PIN.
- Back to the "User Controls", simply check "Use PIN for purchases"
- Note that: On the latest version of the Google Play app this option has been renamed as "Password - Use password to restrict purchases"