Answer:
When there are no available funds in the account, money is pulled from the associated bank checking account.
Another answer
You are required to have two accounts with PayPal. A checking account and a credit card. If you don't have funds in PayPal you can tell PayPal which account you want the funds to come out of.
Another answer
You are NOT required to have two accounts with PayPal. However, you must have a checking account already established with your bank prior to registering with them. When you win a bid and do not have sufficient funds in your PayPal account, they will deduct the money from your checking account if you do not want to pay the balance with your credit card.
Best Answer
Yes, you can. You would add the credit card to your account (if not there already), then set it up as a backup funding source. This way, the money is first taken from your paypal account (up to the amount there) and the remaining from your backup funding source (Credit card or bank account).