I picked up a base 5,1 locally for $200 and have spent a few hundred upgrading it over the past few months. It's a great computer and it's been fun to tinker with one again. Keep an eye on local sales apps (got mine from Nextdoor) and you may find a good deal. There are a few local on Craigslist but they've been upgraded modestly and are >$600 - but they have a full suite of pirated Adobe apps
I picked up set of x5690's from ebay for $150. The cpu's in mine were lidded and I didn't need to delid them. Multicore Geekbench score almost matches my '18 MacBook pro. Bought an Rx 580 4gb from Ebay for $125 and it's working great too. The rest I bought new from Amazon (NVMe, Ram, USB 3.0 card, web cam, etc.)
I picked up set of x5690's from ebay for $150. The cpu's in mine were lidded and I didn't need to delid them. Multicore Geekbench score almost matches my '18 MacBook pro. Bought an Rx 580 4gb from Ebay for $125 and it's working great too. The rest I bought new from Amazon (NVMe, Ram, USB 3.0 card, web cam, etc.)