I supply refurbished Lenovo PC's with my systems that easily meet the specs. I upgrade them with Win10Pro and SSD's. Most users that buy them pay under $200. That's about as cheap as it gets for an up to date PC with the latest OS.

Actually I've never understood the reluctance of users to not want a dedicated, separate PC for CNC use. Guys put thousands into a CNC machine and then skimp on the computer that runs it. Seems counterintuitive.