Lab Jacks, or Scissor Jacks, are not particularly expensive bits of equipment to begin with. As long as you don’t go through VWR, a good 4×4 inch lab jack will cost you $30, and an 8×8 inch lab jack will cost about twice that.
If you want to 3D Print your own lab jack. Thingiverse has several lab jack designs, which can be easily printed as a single print-in-place object.
You might note, that the money spent on the material to produce a lab jack, isn’t that different from the cost of the cheapest lab jacks you can get on Amazon. The benefit to 3D printing is customization. For instance check out this lab jack for microplates that has been printed to work with a stepper motor as part of an automated system.