How do I redeem an iTunes promo code?
From an iPhone, iPod Touch, iPad, etc.
1. Tap the App Store icon on your home page to launch the App Store app.
2. Select the "Featured" tab and choose "New".
3. Scroll all the way to the bottom of the list. Tap "Redeem".
4. Enter your code and tap the "Redeem" button in the top-right"
5. Tap "Done" and you should see the new app downloading.
6. When the download is complete, the new application should be installed on your device.
From a computer running iTunes
2. Enter your promo code in the text field. Click the "Redeem" button.
3. You should see the new app downloading.
4. When the download is complete, connect your device to the computer.
5. Select your device under the "Devices" menu.
6. Click on the "Sync" button.
7. When the sync operation is complete, the new application should be installed on your device.