Why can't I buy anything on my Android device?

First of all, in order to make a purchase, you need to be connected to Google Play. On occasion, Google servers might be overloaded - resulting in your in-game purchases being grayed out. Usually , this resolves itself after a while. In case you are having trouble purchasing in-game currency over a longer period of time, please make sure to check the following:

Check that you are logged in with a valid Google account
Go to your personal Google Wallet page and check your payment method and billing address
Try again after a while, as Google servers may have been too busy to process your order
Update your Play Store application by opening and updating it

If this is not the case, please double-check that you have a valid payment method set up on the Google account that you are using. If you have added more than one Google account to your device, please remember that the Google Play Store will always try to charge the top-most account with a registered payment method on the account list in your device's settings. If your primary payment method is a credit card, you might also want to check with your credit card company whether your card has any restrictions on in-app or online purchases.

If you still have trouble making your purchase, please visit Google Play Store Help Center