I designed and built a CNC machine with 12″x12″x4″ of cutting space. It uses 270 oz-in steppers, a regular old router, a HobbyCNC controller, and Mach 3 as the driving software. It’s accurate down to at least 1/100″. It cost $400 and is made mostly from MDF. Because it is made of wood, it is designed to be very accurate and adjustable.
Originally I designed it for PCB Isolation Routing. Now, ordering prototype PCB boards online is so cheap, that it isn’t worth my time to route myself. It is great for carving wood, making signs, engraving, and other odd jobs. Read more about the design here. I sold it in 2017.