If you don't care about your electricity bill, you can buy used Xeon workstations on your favorite auction site.
A couple years ago, we picked up a HP Z800 workstation with two 12-core processors and 24GB of RAM for $400.
The main downside is that if the power supply (proprietary) or motherboard die, there's not easy fix for it other than buying another of the same model.
I wanted something to host my private and experimental stuff. A friend of mine who tracks used server auctions pointed me at some servers that were Dell systems clearly custom built for one of the large SV companies. I paid $450 for a box with 72GB of RAM and 16 cores. At that price, I just bought a second one for spares. Which I haven't needed to use in the 4 or 5 years I've been using it.
A couple years ago, we picked up a HP Z800 workstation with two 12-core processors and 24GB of RAM for $400.
The main downside is that if the power supply (proprietary) or motherboard die, there's not easy fix for it other than buying another of the same model.