Absolute cheapest CNC chassis?

This is an odd question, with a bit of odd background.

I could use a "scratch CNC" for testing the EtherCAT code that I've been working on for months.  It may never actually mill anything, and it certainly doesn't need to be *good* at anything.  It just needs 3-ish steppers, some limit switches, and the ability to home and move without falling apart.  NEMA 17 steppers would be nice, because there are more options for replacing them.

I'll end up replacing the controller, etc, that comes with it.  Smaller hardware is good, as it needs to fit into my office space.

Is there a downside to just picking up something like one of the cheap GRBL 3018s off of Amazon for $160-200?  I'm sure they're all lousy CNCs, but I'm just looking for the quickest route to having a semi-usable 3-axis chassis.  Is there anything even cheaper that would work?
 

Yes on 3D printer, no on spare rods and bearings. I'm not convinced that spending $140 on a Really Bad CNC from Amazon and throwing all of the control hardware away is more expensive/more work than sourcing linear rods and 3D printing a bunch of stuff.

Nifty project, though.

Something like one of these
www.vevor.com.au/wood-engraving-machine-c_11142
Prices are in AUD so cheap as chips and vevor will be in your country.

That's pretty similar to what I was looking at on Amazon, except I found an even smaller model for slightly less. I'll discuss it with The Budget Committee this weekend and try to get her to sign off on it .