When you add money directly to your Apple ID from a credit or debit card for making App Store, iTunes, and iCloud purchases, Apple is adding bonus credit.
Apple says the offer is valid on amounts ranging from $1.00 to $200, so customers who add the maximum $200 total to their Apple IDs can get a total of $220 from Apple.
Funds can be added to your Apple ID account by opening up the Settings app, tapping on your account name, selecting the iTunes and App Store option, choosing your Apple ID, and then selecting “Add Funds to Apple ID.”
From there, you can see the promotional bonuses available and choose the amount of money you want to add to your account. You can also get to these options in the iTunes Store by tapping on your Apple ID or in the App Store by scrolling to the bottom (or tapping your profile picture) and selecting the Add Funds option.
The promotion will be available from March 10 through March 14 in the United States, and it is also available in other countries as well. To use this feature, you will need to have a valid payment method added to your Apple ID account.