Possibilities for a $500 budget:

- (Cosina) Voigtlander Bessa-R2 (or other models) with a 50mm lens. Good value for the money.

- A screwmount Leica with a clean 50mm Summitar.

- Zeiss Ikon Contax II or IIa with a clean 50mm Sonnar (f/1.5 or f/2.0). I sold several IIa models with the f/1.5 Sonnar for $450 -- one of the best classic camera lenses ever. I don't have any for sale currently.

- Nikon S with f/2.0 50mm Nikkor. You might get lucky on price. Always check the curtains for pinholes.

- Konica II or III. Excellent build.

- Among German classic cameras: Kodak Retina IIC or IIIC, Kodak Retina IIIS, Zeiss Ikon Contessa, Voigtlander Vito III, Voigtlander Vitessa, Carl Zeiss Jena Werra 3,

- I'm not a fan of the Voigtlander Prominent. Big, heavy, clunky, not fun to use.

- I think that the 1970s compact fixed-lens rangefinders are overpriced. They're all good cameras. They just aren't that good. But demand always dictates price, and I think that they've become cult cameras. For a while the Olympus 35 RC was going for $75 or more.