You can buy one on amazon.com or newegg.com for the same (if not less) than you can on eBay, and you'll be assured that it's new.
Watch out for any accessories on eBay as well. I've had an impressive 100% failure rate for batteries, brand name or otherwise. I bought plenty before I learned my lesson... tempted by the $5 prices vs. $50 in a store... but they were all old (not used, just old) and they never held a charge after a month of use. The lenses and cleaning kits and tripods and everything else people sell on there are usually nothing but junk. If you see the word "professional" anywhere in the description, don't buy it. Chances are, it's garbage
A really disturbing trend I think is growing are the sellers that put Buy It Now prices of $0.01 or $1.00, and then charge $24.99 or something for shipping. Who cares where the money goes, right? Shipping vs. item price, what's the difference? Well, guess what gets refunded if the item is defective? That's right, $0.01. I've been ripped off before by a seller who did this kind of garbage and then sent me the wrong item but refused to exchange it. He offered me a refund of $1.00 and got negative feedback instead of his item back.
I've had a few good experiences, but I generally hate eBay.