eBay is working hard to crack doen on fraud, but there are some simple steps you can take as both a buyer and seller to make sure your purchases are safe, secure, and you've purchased authentic merchandise.
#1 confirm you Paypal address... not your ebay address, your PayPal address. If only takes 2 minutes and all they do is match your payPal shipping address to a credit card, but it makes eBay much safer. If someone does get into your PayPal account and goes on a shopping spree, they're not going to want the merchandise shipped to your house! You will also find much less hassle with sellers because sellers want the security that a confirmed address gives.
#2 When purchasing more expensive items, check seller reputation. If you're buying a $150 pair of jeans or a computer or whatever, look for negatives in their feedback. Everyone gets a few negs., but a decent seller should be at at least 97% - 98% pos.
#3 if it's an item that is often counterfitted, do some homework to know what the real item should look like or what documentation need to be in place for it to guaranteed authentic. This is a particular problem eith designer clothing and sports memorbilia.
#4 Always use paypal. Paypal gives you an added level of protection because if a seller doesn't ship an item, payapl will back you up and return the money to your account (and if you're a seller, always ship with tracking so you can confirm delivery).
#5 Read the whole auction, check for shipping policy and return policy. I know many eBay'ers write huge long descriptions, but often in the mix of text you find item specifics you will wish you would have known -- like missing parts, damaged, etc.
#6 If you're searching a keyword, scroll down and see if any guides are available for your item, I have been saved many times buy reading a guide or review after searching for a specific item.