When you give iTunes Gift Cards to friends and family, they can choose whatever they want on the iTunes Store, App Store, iBooks Store, and Mac App Store.
iTunes Gift Cards are easy to give, and you can buy them from Apple and from thousands of other retailers in a range of denominations. And every card works in the App Store for their devices, as well as the iTunes Store and iBooks Store — so your recipients can get exactly what they want.
Add the iTunes cards to your iTunes account, the code you bought will top up iTunes account with the amount you bought. Now you can play iTunes games for free at any time you want whenever you use your iTunes account client.