Players without an Authenticator who wish to use Battle.net Balance:
When attempting to sell an item on the real-money auction house for the first time, players who have not attached an Authenticator to their Battle.net account or set up PayPal for use with the real-money auction house will be automatically directed to the Battle.net website to set up a PayPal account (https://us.battle.net/account/d3/auction-house/landing.html).
If players prefer to use Battle.net Balance as the destination for their auction house proceeds (instead of PayPal), they will first need to attach a physical Battle.net Authenticator or Battle.net Mobile Authenticator app to their Battle.net account. To attach an Authenticator to your Battle.net account, visit: https://us.battle.net/account/management/ebalance-purchase.html. You can also charge up your Battle.net Balance at this location.
Players with an Authenticator who wish to use PayPal:
Players who already have an Authenticator attached to their Battle.net account and wish to use PayPal as the destination for their auction house proceeds but have *not* yet set up PayPal specifically for use with the real-money auction house will not be automatically redirected to the PayPal setup page as they should be. Please note that players will also need to set up Battle.net SMS Protect on their Battle.net account in order to use PayPal with the real-money auction house.
To set up PayPal for use with the real-money auction house, visit: https://us.battle.net/account/d3/auction-house/landing.html
To learn more about the real-money auction house, check out the Auction House Guide and Auction House FAQ.