You can find resellers for brands like UPERFECT all over eBay. The one I used was https://www.ebay.com/itm/313794877980, it looks like they've raised the price since then but I have that exact monitor in front of me and it was definitely $70 when I got it.
That account still sells 4K monitors starting from $100, I only have a sample size of one so I'm not sure whether their descriptions are accurate but they're pretty non-specific so chances are you'll get a brand-new product even if they say "Front/back surface scratches or other scratches issue".
My experience with UPERFECT in particular is that their monitors reproduce sRGB extremely well. I haven't checked the specs for "HDR" mode though, because Windows doesn't properly support HDR.
That account still sells 4K monitors starting from $100, I only have a sample size of one so I'm not sure whether their descriptions are accurate but they're pretty non-specific so chances are you'll get a brand-new product even if they say "Front/back surface scratches or other scratches issue".
My experience with UPERFECT in particular is that their monitors reproduce sRGB extremely well. I haven't checked the specs for "HDR" mode though, because Windows doesn't properly support HDR.