They are great cameras. I have two nice examples and they take excellent pictures.
The listed one is actually only worth close to one tenth of that price.
One recently sold for US$340 and previous ones for approx $100-150. Its a funny market and it kind of depends on who is buying and who is selling at any given time.
The prices for a lot of cameras have been slowly creeping up though, including the FSU rangefinders, for example.
The production run of Zorki 1s was about 800,000, so they aren't _really_ so rare or valuable (as the typical Eastern European ebayer will have you believe).
Also, I find it difficult to believe when someone lists three of the same camera and tries to tell you they're rare!