Honestly, the best price/performance can be had with refurbished Workstation boards that have ECC Memory in it and can be bought for under a few hundred.
Look for Dell or HP Workstations, they are the most ubiquitous. You can probably find a precision tower with like 64 gb of ecc ram and dual cpus for like $500-600. You could even drop down to a single cpu or less ram for just a few hundred.
First result in an amazon search proves me right. 500 for 64 gb ram (ECC, which is a HUGE recommendation), a 480gb ssd 8 core cpu. You save $200 and you can get some beer.