Where to get a cheap extruder?

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.

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The most expensive part of the whole assembly is the hot end. The cheapest i've seen those start in the $50 range. Even if you could build your own hot end for next to nothing the cost of eveything else needed will put you over the $50 mark. But once you have the hot end you can pretty much make everything else yourself. You can find all sorts of design options for making your own extruder assembly. All depends on the setup you have on your printer. You can even print the pattern for the gears onto paper and cut your gears by hand. It wouldn't be too hard to dremel your gears out of 3mm to 5mm piece of acrylic (about $20 or more for a good sized piece of acrylic). You'll want to use a stepper motor in it otherwise you won't have the kind of control you need for good consistent prints. A good stepper shouldn't cost you more then $15 to $20.
jduffy54 (author)  mpilchfamily4 years ago
The acrylic isn't very expensive (lowes has 8"x10" sheets for $1.58, I can't image you need more than maybe two of those), but as for the hot end, where could I get one? Also, do you know where any designs are for homemade extruders?
There are many, many designs for open source extruders. Check out the Rep-Rap Wiki for one location. Making the hot end really needs a machine shop to make a good job of it, but its still do-able with hand tools.
jduffy54 (author)  steveastrouk4 years ago
Thanks, I'm mainly just looking for something that just works, so that I can print more accurate parts for everything, gradually making it more and more accurate as I go.
Thanks for your help.
"$50" and "just works" are not always compatible.
jduffy54 (author)  steveastrouk4 years ago
I know, but according to the reprap wiki, it did seem reasonable to be made by hand. Besides, my xy table is a printer and flatbed scanner. It's not exactly a great setup.
Your cheapest bet may be a modified hot glue gun. But you'll need to reduce the inside diameter of the barrel as well as reducing the tip. Once again this will require machined parts to make it workable. Otherwise the plastic will pass straight through the hot end without ever heating up.
jduffy54 (author)  mpilchfamily4 years ago
What about a mini hot glue gun? I was thinking maybe take that hot end, but what part would need to be machined?
A smaller barrel to fit inside the existing glue gun's barrel. One that is just a little bigger then the filament diameter. Then you would need to machine a reduced tip. One that is about 1/4 the diameter of the filament.