That's a reason no to buy on there.

"Caveat Emptor" or buyer beware is the principle whenever buying anything. ( Latin seems more ominous.)
The biggest difference, is that sellers don't see a sucker coming any more, they know there are so many out there with a mouse, and a credit balance, they just sit back and wait for someone that that thinks something that seems too good to be true really is.
To be honest, most of the people ripped off trying to get something for nothing. Sometimes all they get is experience. Often traders use this idea to justify fraud.

Another saying that fits- If something is cheap you're likely to get your moneys worth.