https://www.serverhunter.com/?search=BF6-4AC-E30 says the cheapest provider with a GTX GPU is Ikoula with an 1070 at 101.66 USD and then Hetzner and then Hostkey. https://www.hostkey.com/gpu-servers
It doesn't find https://dedispec.com/gpu.php these but I do :) I also read somewhere they even accept shipped in GPUs. I know they did with disks.