The listing, $3 Xbox Digital Gift Card has ended.
1. Go to your Microsoft Account page here.
2. Log in to your Microsoft account, if you aren't already logged in.
3. Select "Redeem Card"
4. Enter your 25-digit Promo Code number.
To create a new account, visit www.commerce.microsoft.com. You must be 13+. The full card value will be applied to your Microsoft account and may be used for eligible purchases (exclusions apply) made directly at Xbox Games, Xbox Music, Xbox Video, and other select Microsoft online stores.