Some notes on hardware Vendors for used hardware

Buying used hardware can be a tricky thing. The more knowledge you have the far better your odds of getting what you need. With that in mind there are two basic paths one can take in this regards:
1) Play it safe: when you are not sure - it is best to go to a vendor that fully tests what they sell:
Geeks -
On Amazon:
On Ebay:
KVS Computers "nepateck"
Central Valley Auctions
More will come as equipment is tested
2) Research and take your chances. On Ebay, make sure to check the product pictures carefully and check to see that they are of the exact item you are buying. Some vendors selling stock piles will not post individual pictures - so you can be surprised by what you get. Note worthy:
G-Skill backed a ram stick just as advertised!
2018 updates: Picked up a vintage Dell D531 from huggl.kat (3723) on Ebay - exactly as advertised - great deal!