With a folder camera, the critical point you might want to consider is the presence of a rangefinder. It might be hard to find a Zeis ikonta with coupled rangefinder for under 250$.

Alternatives to Zeis ikonta are the Voigtländer Bessa II: a very nice folder, with excellent lens, and coupled rangefinder.
If you are a little bit adventurous, you can take look at the Moskva line of cameras: they are soviet-era clones of zeiss ikonta. A Moskva 5 should fit in your budget, and can be an excellent camera, if in good condition and well-adjusted.

Cheers