You can redeem an iTunes gift card without a credit card if you do not exceed the total balance of your iTunes gift card. An iTunes gift card can be used to purchase anything in the iTunes Store, including music, movies or TV shows. In order to redeem your iTunes gift card, you must download and install the latest version of iTunes. This will allow you to view the store, make product selections and pay with your iTunes gift card.
Open iTunes by clicking the icon on your desktop.
Click the "iTunes Store" link in the "Source Pane" on the left side of the window.
Click "Sign In" in the upper-right part of the iTunes window.
Type your Apple ID and password into the sign-in area. Click "Sign In."
Select the "Redeem" option from the "Quick Links" window.
Enter the 16-digit code located on the back of your iTunes gift card. Click "Redeem."
Add items to your iTunes shopping trolley up to the balance of your iTunes gift card and check out normally. The total amount of your items will be deducted from your iTunes gift card balance when you check out.