Buyer protection is huge. I sold one gpu on ebay and it all went smooth, then the inevitable "unit didnt work" claim came in months later. It was sealed in the box brand new and PayPal still sided with them. Ebay is a joke. Those prices are usually a ruse
It goes like this. Set up a price for one @ $2k then set up another at $1k and make that look like a bargain. It's a buy trap. Steer clear if ebay and you will be good
Oh, I buy from eBay quite often - but I always do my own research before purchasing. As for selling - I have sold iPads, PC's, Laptops, Cameras, Miners etc - and have had zero returns and zero issues.
There was only one where the person who bought my scrypt miners could not get them working at first, but that was eventually resolved - If I recall, he just need to reset the pool information. The BWL21's were finicky at best and would not always save the information in the UI.