@Noodle11VN
You 'may' be able to use your balance as long as its cleared and not pending or on hold + its in the correct currency.
Also do this........
Click on the profile tab (icon next to log out) > Click on payments third option along on the thick blue band top of page > second down click on update next to your preferred way to pay and put a dot in one of the options listed.
However if you find paypal are still asking you to add a bank account or card then you may have to do so to verify your paypal account and to act as a back up funding source. Even if you can use your balance now you would at some point have to do that to verify your account.
Advice is voluntary.
Kudos / Solution appreciated.
