I've been thinking of buying an internally-geared folding bike for commuting (5 km each way) and errands. I want to spend $100-$200, but I want a reasonable-quality frame; I don't want to ever have to replace the frame with a new one.
Some "Auto-Mini" folding bikes were made in Austria about 50 years ago; I see a bunch for sale on Craigslist in my city.
How are the frames: are they well-made?
How's the bikes' ride quality?
[Edit: I've read that the frames are prone to cracking. Is the Auto-Mini still a reasonable choice, considering the criteria I mentioned above?]