85 Human Warlock
The Bit Players
Step 1: Have an authenticator attached to your account. You may use a physical one (yes, some are sold out, but ANY authenticator, even ones that have skins other than Diablo, will work for your account, so long as you have the correct region) OR you may use the smartphone version.
Step 2: You must set up SMS text alerts through your profile. Log in to Battle.net, go to Security Options, then click on the Battle.net SMS Protect screen. Follow the directions there, then make sure you have the check box ticked at the bottom once you've set everything up.
Step 3: Go to Settings, then My Payment Options. Hit "Add Payment Method", then select PayPal and hit enter. This will take you to a PayPal site where you must enter your PayPal login info to process.
Step 3a: If it works, congrats, you're almost done! You just have to agree for PayPal to share your billing address with Blizzard.
Step 3b: If it does not, then you need to log in separately to Paypal, go to your profile, then click Add/Edit Credit Card. If you don't have a credit card attached, even if you have a balance on PayPal, then you need to attach one. Doesn't matter if you have your banking info on there, I don't think Blizz is accepting that. So attach a card. Then, go to your card's profile, and on the right will be a "confirm credit card" button.
Step 4: Click that button. It will charge your card $1.95 (USD, in this case). Once confirmed, that money will be refunded to your PayPal account...and pretty damn quickly.
Step 5: Hopefully you have online banking. Go to your bank, log in to view your card's history, and there should be a charge from PayPal listed. On that charge, it'll say something like "PP*1234 CODE". You may have to wait a day or two depending on your bank; mine showed up instantly. If you don't have online banking, you'll have to wait for your statement.
Step 6: Go back to PayPal, and underneath the Edit/Remove buttons will be something like "Enter PayPal Code". Click that, and enter JUST the four numbers that were on your charge (whatever numbers replace the 1234 in the example above.)
Step 7: GOTO Step 3 above. If that doesn't work, then you'll have to contact PayPal for more info.