As you become familiar with eBay you'll soon get a feel for which auction listings are shady and should be avoided, almost a sixth sense that many longtime eBayers develop.

Naturally, you should always begin by checking a seller's feedback profile before bidding. Until you develop that additional sixth sense, however, here are ten signs beyond mere bad feedback that should be seen as red flags when you're considering a bid.

1.Very low Buy It Now price. Especially when the item is a very desirable computing or consumer electronics item, a Buy It Now price for a brand new item that is significantly below fair market value should set off alarms. Even on eBay, there is no way to get a brand new $5,000 plasma TV for $1,800.

2.Items that don't exist. Don't bid on any auction for a big-name manufactured item that doesn't exist in any store, because in all likelihood it doesn't exist in the seller's inventory, either, or if it does, it's illegal.

This includes items like DVDs of films that aren't out on DVD yet or things like "never relased" computer systems with processors many times faster than those for sale from major manufacturers.

3.Unorthodox or untraceable payment methods. PayPal is the gold standard for online payments at eBay, and when PayPal isn't available, money orders do just fine. Steer very clear of sellers who request untraceable wire transfers or bank account information for "e-checks."

4."Untested" items from sellers that only seem to sell "untested" items. More often than not in such cases, "untested" is just another way of saying "broke." Beware that even if this seller is an honest liquidator who really doesn't know if it works, you still only have a 50/50 chance of receiving a working item.

5."Almost the real thing" items. Watch item descriptions for rip-off games like "SUIT not BY ARMANI, EXQUISITE!" and "GENUINE INK like EPSON BRAND!" and check descriptions closely for phrases like "GENUINE COMPATIBLE MANUFACTURER'S PART." Whether the word is "not," "like," or "compatible," what it really means is "FAKE."

6.Astronomical shipping. Too often new buyers are taken in by the $0.01 Star Wars DVD... only to find that shipping will be charged at $99.99. Even if you get the DVD, you've overpaid by a serious amount, and let's face it, do you really want to take a chance doing business with a seller like this at all?

7."Contact me before you bid" listings. When you do contact sellers that put this key phrase in their description, they'll tell you that you can buy direct from them, bypassing eBay. Then they'll take your money and disappear, and eBay won't have any record of the transaction, so you won't even be able to leave negative feedback.

8.Out-of-place items. Think twice if a seller you've bought vegetable seeds from in the past has suddenly transitioned to selling brand new high-end camcorders. This if often a sign that the seller account has been compromised or hacked by someone who will take your money and deliver nothing at all.

9.Contradictory information in listing. Did that 250 gigabyte hard drive become an 80 gigabyte hard drive after you clicked on the item to see its listing, or did the 36 inch color TV become a 20 inch set lower down the page? Don't automatically assume you'll get the better of the deal, because most of the time you won't.

10.Seller-absent listing. When you see a listing that seems completely generic, as though a features list were copied straight from a book and the photo was taken straight from the box, and there's no additional information to let you know anything about the seller, think twice before you bid. This often indicates that there is no actual item for sale, and that this seller actually did copy the description from a book and the photo from another website, and is now trying to sell an item that he or she doesn't actually have.

Though it's always tempting to want to see eBay as an entirely safe place for fun trading and great deals, if you keep an eye out you'll see a surprising number of listings that fall under these criteria. Just be careful to avoid them as you evaluate potential buys and you'll go a long way toward making your eBay experience a better one.