Q: How long do I have until my iTunes gift card balance expires?
A: Once your iTunes gift card has been applied to your account, the balance will not expire until it has been used.
Q: How can I use my iTunes gift card balance?
A: Your iTunes gift card balance can be used to make any purchase in the iTunes Store. This includes music, movies, TV shows, ringtones, audiobooks, apps, and even towards any ongoing subscriptions that you might have, such as Apple Music.
Q: What happens if my iTunes account balance is not enough to cover the cost of my purchase?
A: If the credit on your iTunes account is not enough to cover the cost of your purchase, then the remainder amount of the purchase will be applied to the primary payment method on your iTunes account.
Q: How can I see the remaining gift card balance on my account?
A: You can view your current credit amount through the iTunes Store app on your iPhone. Specifically, this can be found at the bottom of the Music tab, under your Apple ID. This article explains in further detail, and provides pictures as well.