I was about to get a mining rig and did a lot of research. In my country (Croatia) the prices stayed the same because people didn't buy so many GPUs. But as I saw it would cost me to much because difficulty was increasing every day big time.
Best card out there is amd RX 580 4GB. It has the best price /performance ratio.
Saw also a Xeon builds but I don't know if it is worth of buying it on the other hand if you have few old servers it is worth a shot