@handy333 what businesses use is an entirely different class of 3d printer (unless they run print farms then they just use the cheapest reliable commodity consumer 3d printers they can get)
The closest thing you can do is build a machine to cut PET water/juice bottles into plastic strips and form it into filament. I've done this, it's a neat project just for the hell of it but it will never pay off.
the reason filament costs as much as it does is not because plastic is expensive, plastic is cheap but making the filament is complicated and time consuming