If you don't know about the Green Pages...there are reputable sellers listed under Tools & Apps...but we have all been there with ebay!
I ordered a pressure cooker on ebay, it was never sent (the tracking number told it was not in UPS hands), although ebay could not actually do anything because of how this guy had worked it, Paypal refunded our money.
I also got black hollyhock seeds from "toad stool seeds" (Yeah should have been a clue) that turned out hot pink! They had fabulous reviews, but were horrible when I notified them of the mix-up. Then I realized all the reviews were on how fast they shipped, never on the seed being correct.
On the other hand, I have ordered lots and lots of shrubs from dogwooderitternet, they pack them well, but they have to be babied because they are just tiny. (Many bigger plants don't establish well for me or I would get the bigger ones.) Even then, someone from here got a peony from them that did not grow and they gave/got a refund.