Most of the suggestions you will get in response are from those who own and use the camera they will be recommending. That's a good thing. The key is to look for recurring patterns in the responses. So I'll go ahead and start it off with the...
Good to very good samples can be had for US$125, or less. My particular sample was purchased from a fellow APUG member for around US$85-90, as I recall. It was - and remains - in excellent user and cosmetic condition. I have a large number of cameras in formats from half-frame 35mm up to 8x10, and it's one of my top favorites.
[Edit: The above link mentions that the camera requires the now discontinued PX625 1.35-volt mercury battery. You should know that this Canonet can also be adjusted (not modified) to meter correctly when using the easy-to-find 625-form 1.55-volt silver cells. There is a variable resistor under the top cover to accomplish this recalibration. (I have the original adjustment procedure instructions.) Mine was recalibrated before I purchased it and it works very well.]