Recently, I received an offer from American Express, where I would receive a statement credit if I used my card on iTunes. Unfortunately, I already had a gift balance on my Apple ID and didn’t expect I’d spend it before the promotion expired.
I used the following steps to charge my card immediately and just add to my account balance:
- In iTunes, go to the Store menu -> View account (appleID@email.com)…
- Edit your payment details to the credit card with the promotion.
- Click the home (icon) button near.
- Under Quick Links on the right hand side of the window, select Send iTunes Gifts.
- Enter your own email address, select an amount that qualifies for the promotion, and click Next.
- Pick a design and click Next.
- Click Buy Gift to charge your credit card.
- Look at your email for an iTunes Gift card you can add to your account balance.
- Switch your credit card back to your original card.
Note: I’m not sure why it isn’t possible to buy/send gifts from the Mac App Store. As far as I know, you have to use iTunes.