You can get Dell T3610's off of eBay for $150-200. Many are coming off of a 4 year warranty. Perfect working order, well-maintained and you'll find some with graphics cards supporting 3 monitors. They can last another 4-5 years easy. Plenty fast for trading. They'll come with Windows10 Pro. Make an image copy of the hard drive, ditch it, transfer to an SSD. Done.
The T3600s are 2 generations back. More like about 6 years old... still worth $200, however. (1 generation back = T5810. Current generation = T5820... very much a new design... and a BIG upgrade to the 5810.)
Yup, T5820 is a pretty good platform. Will last another 10 years easily. Most folks who never experienced the differences between real workstation engineering and consumer or U-Build stuff will not appreciate it though.
The T5820 is certainly evolutionary if not revolutionary. Many more will be made like it in the future.