From what I've seen, that $750 is in the right ballpark for a "refurbished/rebuilt" tiller with new bearings, seals, chain, etc. (maybe tines too, but I understand the original curved blade hardened ones are no longer available), and paint. I got my very nice used Yanmar RS1202 (48" wide 2-pt type) for only $250.00 but it was not refurbished and I had to convert it to 3-pt. You should be able to get a "good" used 3-pt Yanmar tiller for no more than $450 to $500 and probably a little less, from what I've seen advertised.
Bill