paying apple card with apple gift card or...?

Here is what you can purchase with a Gift Card.

What you can buy with your Apple Gift Card or Apple Account balance - Apple Support

There are a couple of types of Gift Cards. One is used for App Store purchases and subscriptions made with in-app purchases. There is also an Apple Store gift card for purchases at a physical Apple Store or Apple.com. To identify the Gift Card you have, you can check here:

What type of gift card do I have? - Apple Support

There is no way to convert a Gift Card balance to cash or be able to pay an Apple Card balance.

If you are like me and don't have a CC and you are at a Apple Store you can purchase Gift Cards to purchase Apple Computers or iPhones or iPads. For some reason Apple Stores don't want you to purchase Apple products with cash but you can purchase gift cards. I am still trying to figure that system out.

Here are a couple of things to consider:

• Most countries are now putting strict controls on minors purchasing content or having access to content. Apple also has age ratings for apps. When a person sets up an Apple ID, they simply put their birthdate in without needing to provide any verification. Having a valid payment method is a way to verify that your birthdate is correct when you do make purchases.
• Apps and Subscriptions may be different depending on the region of the App Store you are using. Some of them are not available in all regions. While it is easy to change the region on your device, you do not need to provide any identification to prove that the region is correct. When make purchases, the payment method must match the region that your device is set to.