I use old HP Proliant as a workstation. For $900 you get 24 cores and 256GB RAM. Its pretty loud and power inefficient, but works great for testing concurrent and memory intensive code.
That's 1500USD. I'm sure 900USD is possible if you keep an eye out, seems like a pretty sharp deal though.
I haven't found any with shipping (to Denver CO) more than ~$100. $2k sure is a bit steep....