I am reposting my previous comment from the "See my Art" contest here (with a little editing). It seems very appropriate!

As an ebay buyer and seller, I have to stick by it. I have met incredible people and been introduced to some amazing minds.

I think that as with any other "site unseen" art purchase you have to be wary, but there are ways to gain confidence in the art you are purchasing. Always ask to artist/seller questions, if you have them. Dont be shy!! I know that I get requests for technique description and additional photos all of the time.

Ebay is a fantastic venue for Self-Representing artists. We have the opportunity to reach people all over the world, who may not have seen our work otherwise. Be sure to check out Suzy Keely (keelyart) and Mikel Robinson (m-art-r). I own one of his lightboxes. It is gorgeous!

It's a mixed bag. I once got 6 beautiful high-quality prints by illustrator Luba Lukova for $2 each (actually less, because I bought four prints and she threw in two that she had lying around). But I've also been ripped off--I bought what was supposed to be a Lynd Ward print, and I specifically asked the seller if it was a real print or just a page from a book advertised as a "print." She claimed it was a real print, but now that I have it I'm certain it's just a page from an old edition of one of his books. $30 wasted.

Mikhaela -
Actually, it kind of depends on the book! The print-making techniques of illustrations in old books were often exactly the same as other prints -- engravings, (real) lithographs, etc. -- and just because it came out of a book doesn't make it NOT rare and doesn't make it NOT a print.

If it's a pretty recent book, then it may be different, but for instance, a friend bought a book on eBay for like $5 because nobody but him knew from the title that it had some actual Picasso lithographs in it, which are really rare, because most of the books have been pillaged for those lithographs.

I'm just sayin'.

I've bought some great work off of ebay, but agree that you have to be careful. I find it's best to do research online before bidding. Usually, the object (or something very close to it) can be found elsewhere, which makes me more comfortable to bid and gives me some idea on a reasonable price. Sometimes, I've found the exact same thing cheaper on another Web site.