meisteg
commented
11 years ago Useful link: http://www.localwisdom.com/blog/2013/03/android-in-app-billing-server-verification-and-content-delivery-2/
Other related links: http://developer.android.com/google/play/billing/billing_best_practices.html http://developer.android.com/google/play/billing/billing_integrate.html
Interesting, but I don't think it is needed in this case: http://developer.android.com/google/play/billing/gp-purchase-status-api.html
Allow user to submit answers late (inside a certain window) for a fee.