Can I pay for Apple Music with just my apple account balance? I don’t have a credit card.

You can pay for Apple Music with your Apple account balance. See What you can buy with your Apple ID balance

"Find out what you can buy with your Apple ID balance.

Pay for subscriptions such as Apple Music..."

Just make sure that Apple Account is your payment method - and that it has a credit from which to draw. Change, add or remove Apple ID payment methods