How do you buy stuff online with iTunes credit

Your iTunes credit is the same as your Apple Account balance. If you are in the USA, or a few other countries, you can use your Apple Account balance to purchase items at the online store and a variety of other online Apple services.

To learn 'What you can buy with your Apple ID [Apple Account] balance', click here --> https://support.apple.com/HT211187

"Where the Apple Gift Card is available, you can use your Apple ID balance to buy products and accessories at apple.com or in the Apple Store app."

For a list of countries where the Apple Gift Card is available, Click here --> https://support.apple.com/HT202631 and search for 'Apple Gift Card'

(Nov 25, 2021: the USA, Canada, Australia, and Japan)

https://www.apple.com/shop/gift-cards --> "Apple Gift Cards are solely for the purchase of goods and services from the Apple Store, the Apple Store app, apple.com, the App Store, iTunes, Apple Music, Apple TV, Apple Books, and other Apple properties." This list does not include retail Apple Stores.

Terms and Conditions for Apple Gift Cards and Codes, Apple Account Associated Balance, and Content Codes

https://www.apple.com/legal/internet-services/itunes/giftcards/

- "However, only physical and digital gift cards and codes can be used towards purchases in Apple Retail Stores. Your Associated Balance cannot be used for purchases in Apple Retail Stores."

You can't use your iTunes credit to buy on line. See the Apple Support article(s) below.

Apple ID balance - What you can buy with your