PCB routing machine, with a software suite to create designs and control the steppers to make that design a real life thing. Current cost of materials if I made it from scratch now is about $230, not including the cost of the 3d printer.
Cheap liner motion system to replace expensive Liner rail. Compatible with HIWIN Same thickness and screw position. Material used 625 bearing ptfe tube cut to length screw Hex nut shaft Maybe something for Printer Chat?