For what it's worth: I've had good luck on ebay over the years, but won't buy from any seller with less than a 99.5 rating.
Cranks can sometimes tarnish an otherwise reputable seller but, given enough transactions, the averages eventually make up for the cranks.
I also avoid non-North American sellers - preferrably US only, via 'buy it now', and with free delivery (lol :)
Given the bargain prices of many of those listings, you could buy one from several different sellers, likely get at least one good one, and still by $$ ahead.
Even if you should end up with a loser or two, you won't be out much.
Cheers, and good luck !
I see a doctor, complete with stethoscope standing behind Trump. Lol - nikos! Is that you?