According to PC World this is why a very high supply and demand due to mining ..... 
.!!!!!
http://www.pcworld.com/article/3199257/components-graphics/why-amds-radeon-graphics-cards-are-almost-impossible-to-buy-right-now.html
.!!!!!http://www.pcworld.com/article/3199257/components-graphics/why-amds-radeon-graphics-cards-are-almost-impossible-to-buy-right-now.html
No kidding, I actually had some RX 580's laying in a mining rig just mining ethereum... and I originallly got them for about $229 each. I just sold them on ebay because of the high demand and got $385 for them each. (I'll be buying more once the price goes down.) Just mining with different gpu's now.
Don't sell GPUs on eBay for such a high markup.
The market can turn and the buyer will just send those GPUs back to you claiming they were broken due to Paypal protection policies.
Please shut the hell up, as a seasoned eBay seller with a large volume store you know absolutely nothing. Ive had this happen to me ONCE (out of hundreds of GPU sales) and I easily won the case. There is NO implied warranty when selling a card on eBay unless you take it upon yourself to offer one.
Sold a guy a FirePro card, he claimed it broke 3 months later, filed a case through PayPal directly, I called up PayPal and they agreed that he was out of line. If you buy a used car from a dealer and the transmission blows 3 months later the dealer is not responsible, same thing here...
Buyers then usually do a chargeback through CC but paypal seller protection kicks in and you are covered.
