Score!!! When ordering from the official App in the Air store, make sure you have your gift card code on hand for the billing and payment phase. In the payment section, select the "Gift Card" option, enter your unique code in the box, and click "Apply". You can use this code until you run out of a gift card balance. If your gift card balance does not cover the total amount of your order, you will need to enter another method of payment for the remaining amount.