$600 is probably fair. Unless you know the person you're purchasing from its just kind of difficult to trust that everything about a 50+year old camera will be in good shooting condition. That's why I suggested Youxin Yi when purchasing the camera, it just takes the worry about possibly needing a CLA out of the purchase--you'll pay the same for a freshly CLAd camera from him as you would for one that likely needs a CLA from a private seller. As for the lens, it's easier to trust the descriptions of private sellers. As long as it doesn't have fungus, separation or extensive haze you'll be ok. A Summitar in good shooting condition will probably sell for anywhere from $225-$350.