Cheapest 3d printer possible

Goal is to make a 3d printer with a build volume of 200mm by 200mm by 200mm. To help build future projects. Theoreticly as cheap as physicly possible. Due to printers being 300$ and up! I think I can make it cheaper! Not better but one with my tiny 100$ barely moving 3d printer. I made some V linear chassis for my 3d printer to print 20x20x90 chassis but that will take 1 day and 5 hours to print I also lost the microsd card so will have to run to the store soon!