@Ari_
Firstly as a buyer you don't need funds in your balance as paypal will auto-take from any linked bank account or card on your paypal account. Having said that if you 'only' have a bank account you can still use it as a funding source but will have to wait echeque clearance unless you have a back up card linked and confirmed on your paypal account as well.
Secondly you can set your preferred funding source OR change it during checkout.
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.
Lastly if you want to add funds then have you added a bank account (not card) and did you confirm it with the 4 digit code as per link?
https://www.paypal.com/au/cshelp/article/how-do-i-confirm-my-bank-account-with-paypal-HELP185
If all that doesn't help then you could try another browser or device or contact customer services for more trouble shooting?
Advice is voluntary.
Kudos / Solution appreciated.
