I paid about $50 on Ebay for mine (QL17 GIII) last year, and if I had to do it over, I would probably go with the advice here and buy from somebody here or somebody who has a good rep.
I got one of those "it looks fine but I don't know anything about cameras so it's sold as is" deals. It turned out to have a stuck shutter, a bent internal tab on the shutter speed ring, and petrified light seals. I got my baptism by fire in camera repair getting that thing working! Some Ronsonol and a light seal kit from Jon Goodman were all it really needed.
But anyway, the last time I checked Ebay, the used ones in take-yer-chances condition were going for around $50 or so and the ones that were recently CLA'd and working fine were $120 to $150 or so.