, paypal has fees for everything. For receiving money and withdrawing money. They are owned by ebay, so if you are an ebay seller, you will get raped with fees every step of the way. From initial listing, end auction sale price, receiving money from the buyer and even withdrawing the money (If you do it through an atm or at a bank teller).
I suppose if you are just spending money then no, you wouldn't see any fees.
I would say, if you are shopping on ebay, its essential, but if not, don't even bother, just use a credit card, less bs.