Do note: these aren’t a great option if you’re on Linux, since they no longer receive driver updates, and likely won’t work well on Wayland based systems due to that. You’d probably want to opt for an AMD Vega 56 instead for something that’s similarly powerful that can use the open-source driver, though I believe it’s a little more expensive.
I was basing that on what he mentioned at the end, but you’re right. Checking ebay, it looks like they go for around $80 buy it now, and around $50 w/ shipping for auctions.
Cheapest one I see is $117 + $30 shipping on eBay, so even that number is going to be regional.
True, PC part prices can vary dramatically depending on the country. The prices I mentioned are for the US region, specifically.