I'm not sure there is such an animal as a "cheap" buffalo chopper. You'll find a used one "cheaper" than new - but it still isn't going to be cheap.
I'm not a big eBay fan - but sometimes you can get a good deal there. I looked over the buffalo choppers listed and I would really shy away from the cheapest one ... unless you want to have it shipped directly to Hobart for refurbishing - which means it's not going to be as cheap ... and since it already has 26 bids on it I'm guessing it will probably wind up going for about $450-$500 ... plus another $100-$150 for shipping. The next best one is in Long Island, NY - for $900 - but it's pick-up only, no shipping. That leaves the one for $1,600 - and it's a 200-Volt model so you would need the electrical wiring to handle it.
Check your newspaper under used restaurant equipment. Also check your phonebook for someone who sells used restaurant equipment, or even someone who sells Hobart - they would probably know of a used one for sale. If you live in a small city - it would be worth checking out the same newspaper/phonebook sources in a large city near you.