"Once you sign up for PayPal, you can send money to anyone with an email address and we will deduct the money from your PayPal balance or charge your credit card. Recipients are notified by email that they have received a payment."
So the one who wants to pay you money just sign up with paypal and make the payment to your email address with their credit card. Right?
It seems that a lot of people selling things on ebay prefer this method. Anyway, I've never used it so I could be wrong.