This article explains how to redeem prepaid codes so you can make Xbox purchases and extend your memberships. It also explains how to check your Microsoft account balance.
Prepaid codes usually come in the form of cards with a 25-character code on the back. You can purchase them yourself from a retailer, or you might receive them as a gift. You can use prepaid codes to make purchases without a credit card. You can redeem prepaid codes on your console or on a computer.
Note If you’re on the Xbox 360 Entertainment For All Plan (US only), you cannot “stack” or combine prepaid subscriptions during the life of the contract. If you cancel the subscription before the end of the two years, you will be charged an Early Termination Fee and any applicable taxes.