Xbox LIVE subscription (Internet Required)
The easiest way to redeem a pre paid code is to use the Xbox LIVE Web Marketplace. Via a single location on xbox.com, you can redeem all types of pre paid codes and have them applied to your account immediately.
1 - From xbox.com, use your Windows Live ID to sign in to your Xbox LIVE account2 - Select My Account from the My Xbox drop-down menu.
3 - Click Redeem code to apply the additional pre-paid time to your existing credit card-based subscription.
4 - Follow the instructions that appear on the screen to enter and to confirm the addition of the pre-paid code.
Xbox 360 console (Internet Required)
In the My xbox area -> select the Xbox LIVE profile -> select Manage Account -> then select memberships
Select the current membership, and then do one of the following things;
1 - To convert your account to a pre-paid membership, select Change Payment Options then select Redeem Code.
3 - To apply the additional pre-paid time to your existing credit card based subscription, select Redeem Code4 - Enter the pre-paid code, and then select Done to continue.
Updated: 03 November 2012