Paypal is really not very good at resolving problems. I think it's worth now that they were bought by, and integrated into ebay. However, if you use paypal and use a credit card, you can always fall back on calling your bank and stopping the charge on the card as a 'rude last resort'.
If you're interested in buying stuff from people here, there is a thread in this section called "good guys" - people who have sold stuff and had satisfied sellers.
Another thing I would take into consideration is length of time here - each of us have in the corner of our profile a joined date, as well as the number of posts. Someone who's been here for several years is less likely statistically to screw someone over than someone who's first and only post is "I'm selling these 20 things". Not that a new person would automatically do that - not saying that at all. Just suggesting that someone who has been here a while and has a reputation, might think twice before being a prick.
Same applies to ebay actually. I rarely, if ever, buy items from sellers with less than 50 feedbacks. Sellers with negative feedback I read the feedback thoroughly and for the most part one can determine if the seller, or buyer was out of line. It's usually pretty easy too. One seller had a "buy it now" price that was fantastic on a measuring instrument I wanted for my lathe, however he had three negative feedbacks in the last month. After reading through, they were left by the same person, who left negative feedback with "You suck, bite me!" in the text. I clicked over to her profile, and saw that she leaves that feedback on every auction she wins. EVERY AUCTION. So I concluded the seller of this measuring instrument wasn't going to cause me worry, and sure enough, the item arrived in 2 days, as promised, as described.
Buying and selling on ebay, here, or in the newspaper requires common sense. If you have any doubts whatsoever about a seller or an item, skip it. Tomorrow you'll find the exact same thing for sale by someone else. What gets most people into trouble is the impulse purchasing that ebay clearly encourages.
