Why is the App Store asking to add a payment method for free apps?

You don't have to pay anything to download a free app, but you may still find you need a valid payment method. If an app requires you to have a subscription, then that is from the app developer and nothing to do with Apple. You will find that developers of apps are not spending their own time and money to make apps available without those optional methods of payment such as subscriptions or in-app purchases. Many also have free trials that will automatically be converted to a subscription if you do not cancel at least 24 hours before the trial period ends. They are free to download, but your card will be charged if you use those optional payment methods.

Add a valid payment method and you can download all the apps you want that are labeled with the Get button to download it for free. Depending on the app, you will have additional options that may require payment. The developer hopes you will find their app useful enough to further support them. They are not putting the money and work into the app just to give it away. I would suspect you would not do that either.

Now specifically for subscriptions that it sounds like you have signed up for. You must cancel the subscription to avoid any renewal and they do not cancel simply because you no longer use them. This is the same for any company such as a streaming service where it will auto renew and you will be charged whether you watch the shows or not. To cancel any subscription that is managed by Apple, you can easily do that here:

If you want to cancel a subscription from Apple - Apple Support

If you owe money from any purchase/subscription, you will not be able to use the App Store until that has been paid. I think that is reasonable.

Apple's official support articles present multiple statements* about situations requiring the presence of a payment method at times, even for free items. You do not always have to have one, but if you are encountering one of those situations then you have no option but to enter a valid payment method if you wish to continue your purchase. The payment method may not be charged if you also have account balance or the item is free, but the payment method has to be present. You might even be able to remove it again immediately once Apple has seen it.

This next article lists valid payment methods for different countries but note that in this situation Apple Account balance alone apparently may not meet the requirement and you need to use another payment method until you find one that satisfies Apple's requirement (often a credit or debit card): Payment methods that you can use with your Apple Account - Apple Support .

If you have already entered a payment method, use the “Add a payment method” link above to check it. If a message appears in red there is a problem with it. If the information is still correct and current, contact your financial institution. Also check this resource --> If your payment method is declined in the App Store or iTunes Store - Apple Support

* Ref.:

Add a payment method to your Apple Account - Apple Support

"To make purchases from the App Store and use subscriptions like iCloud+ and Apple Music, you need at least one payment method on file."

If you can’t download or update apps on your iPhone or iPad - Apple Support

- "You might need to have a payment method on file, even if the app that you want to download is free."

Remove a payment method from your Apple Account - Apple Support

- If you have any active subscriptions, you must have at least one payment method on file other than Apple ID credit.

- You might not be able to remove a payment method if you have a balance due.

Sign in to your Apple Account - Apple Support

- "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."

How apps, content, and subscriptions from Apple are billed - Apple Support

- You can’t charge gifts to your Apple ID balance. If you send a gift or gift card, your primary payment method is charged.

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

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."

Hello~ Also in addition to *Mac Jim ID’s* excellent post …you are speaking to other fellow forum users here and not Apple. We have no access or control over your accounts. If you owe Apple money that will need to be cleared up before you can download or update anything.

~Katana-San~