Buy yourself a big hand crank unit like we did years ago...put literally tons of deer through it. It was around 49 bucks or so. I reworked the cutters a bit to make them more flat and sharp.
Just recently I got smart (kinda ironic cause the kids are much bigger and much more capable of turning the crank) and cut the keyway off on the shaft (where the handle would screw on) and welded on a 1/2" socket which allows me to hook up my 28 volt milwaukee drill on....put it on low and grind away. Probably only took 5 minutes of actual "drilling" to do a deer (and we grind the entire deer except for the tenderloins).
Kids said "Dad - why'd you wait so long to do that?"