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Is it you cannot pay using account balance, or is it just that it asks for you to enter a payment method?

Sign in with your Apple ID - Apple Support - at the very bottom: "When you sign in to the App Store and other media services for the first time, you might need to add a credit card or other payment information."

Also:

How App Store and iTunes Store purchases are billed - How apps, content, and subscriptions from Apple are billed - Apple Support

Some purchases aren’t charged to your Apple ID balance

- Some subscriptions might not be charged to your Apple ID balance.

And:

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

"Some purchases might require that you have a credit card on file, even if you use your Apple Account balance to make the purchase."

So, the resolution will be to add a payment method:

This document explains how to change, add, review, or remove Apple ID payment methods on a Mac or Apple mobile devices; click here --> Add a payment method to your Apple ID - Apple Support