Honestly, the biggest problem you are going to have, when buying any 30+ year old rangefinder camera, is finding one that works well. One of the main problems will be hazy viewfinders, sticky/stuck shutters, and inoperative light meters (if the camera has a built-in meter). Consequently, I'd say just stick to finding something that works properly and is within your price range, especially if you are just wanting to try out rangefinder-type cameras without any serious investment. Any of the old Canon Canonet cameras with an f1.7-f1.9 lens would be great, and typically sell in "working" condition on eBay for under $100. The earlier, larger Canonets are nice cameras and often sell for much less than the later G-III QL17 model.The Konica Auto S2 is also a good option, and can typically be purchased and fully CLA'd by Weber Camera (specializes in Konicas) for around $150 in total expenses. These earlier Canonets and the Auto S2 are fairly large cameras (about the same size as an SLR from the period). Another popular option and MUCH smaller is the Olympus RC, but these are getting pricey (around $100-$150 for a solid working example).
With patience, regularly checking the classifieds section here at APUG and at RFF (Rangefinder Forum) could yield some good options.
The Zeiss Contessa... IMO terribly over-rated. They are a good camera, but certainly not the epic jewel that people make them out to be. They can also be fairly expensive for guaranteed working examples ($100+). And yes, I've owned/used one before. It was... OK...
I've also never liked the Zorki 4 models... their viewfinders are a bit weird (it's difficult to see the entire frame when looking through one), the winding is a bit weird (the step in the top plate is WAY to close to the winding knob), and of the 4-5 examples I've had they never really inspired much confidence in their reliability. If you want to try out a Russian RF camera, I'd suggest something like an FED 2 or a Kiev 4. Fedka currently has a Kiev 4a listed for $109. However, I will admit that the Jupiter-8 lens that is commonly included with the Zorki 4 is indeed a great little lens. A classic Canon LTM body with a Jupiter 8 on the front is also a good option.
If you don't have a good handheld light meter, you might want to consider getting one. That will open up a LOT of options for great classic rangefinder cameras if you still want to be make accurate exposures (unless you are uncannily good at estimating exposure yourself).
Personally, I would go with finding a clean Konica Auto S2 and then sending it in to Weber Camera for a full CLA and battery conversion. It will likely cost a bit over your budget, but you'll have a freshly serviced camera with a nice lens, excellent viewfinder, and built in meter. Everything that you'd want in a daily-user rangefinder camera.
