Where is the cheapest place to get an extruder for a 3D printer? It must be premade (preferably a DC motor, not a stepper), and cannot require that I buy separate 3D printed parts. Unfortunately, I cannot use Ebay, however, I can use most other online retailers. It must be below $50, and if thats not possible, is there any way to make one with commonly avaliable parts (no 3D printed ones or milled parts), also cheap? It does have to be fairly small, but need not use the premade spools of plastic, if an epoxy or solething else exists that would also work. (and I have already seen the glue gun extruder instructable here, that is far too big and heavy)
I know that most of this is a long shot, but I'm hoping someone knows/has heard of one of these.