Cheap and old, let me mention the Agfa Super Solinette and its twin the Ansco Super Regent.
They feature an unbelieveably sharp, unit focused, f/3.5, 50mm Solinar, which is a Tessar-type lens, a Synchro-Compur shutter with a full range of shutter speeds and the camera folds to fit in your pocket. The Super Regent sells for in the US for as little as $15.00. The down side is they all need their helicoid grease replaced, as the Agfa grease gets pretty stiff with age and there is no built-in meter.
Another couple of pocketable folders, which get passed over, but have a superb Scheider Kreuznach, f/2.0, 50 mm Xenon, is the Kodak Retina IIc and IIIc. These are well under $100 in the US. The IIIc has a built-in meter and is similar to the over-priced IIIC, but with a slightly smaller viewfinder.
Mike Elek's recommendation for the Retina IIS is good one. The IIS has the same large, bright viewfinder as the over priced Retina IIIC, but without the busy framelines for the auxillary 35mm and 80mm focal length lenses. The IIS is a non-folder, without interchangeable lenses, so it does away with the annoying frame lines for the tele and wide-angle lenses.
Having a folder is nice, but the big selling point on the Retinas should be that the Schneider Xenons and Rodenstock Heligons are amazingly good renditions of the Zeiss Planar. Again, you get a Synchro-Compur, which features a full range of shutter speeds from 1/500th to a full second.
Although they may be 50 years old, the above folders match or exceed the later Canonets and Electro 35 compact range finders in image quality. The build quality is first rate. In addition to folding to a size that allows them to fit in your pants pocket, these premium German range finders will never need their light seals replaced or require a difficult to source battery cell, because they didn't use them to begin with.
By the way, the above cameras are manual mode shooters, there is no automatic exposure feature.