Apple is rolling out a new promotion that offers customers a 10 percent bonus when adding funds directly to their Apple ID account in the United States between December 17-20. The bonus applies once on up to $200 and was first highlighted by Japanese blog Mac Otakara.

The funds can be used towards purchases on the iTunes Store and App Store, an iCloud storage subscription, and so forth.

To add funds directly to an Apple ID, go to Settings > Your Name > iTunes & App Store and tap your Apple ID > View Apple ID. Sign in if necessary, tap "Add Funds to Apple ID," tap the amount that you want to add, and confirm your selection. There's also a shortcut available at the bottom of the App Store.

Adding funds to an Apple ID requires having a valid payment method on file and is particularly useful for prepaid credit cards.