I got into folders for exactly the same reason that the OP states, that I wanted to use medium format but didn't want to cart my usual gear (an RB67) around. I wanted something I could slip into a coat pocket (you can't do that with an RB67) and that was pretty cheap but fun. I've ended up with a couple of Ikon Nettars, an early uncoated 510/2 6x9 Novar one for monochrome and a later 517/16 6x6 one for colour. Both cost me less than £20. They are simple enough that if any work needs doing on them you can usually do it yourself, and then if you foul things up, it doesn't matter. It's also lovely working with a camera that has some 80 years of history and use behind it. I'd love a later version Super Ikonta but the prices they go for are crazy. If you're patient you can get a decent pre-war Nettar for less than £10, I've seen them in charity shops for £5 (which is why my 'will get around to servicing those' pile is now getting quite big). There are a whole range of different lens and shutter combinations The early ones have often limited ranges of shutter speeds and pretty slow lenses. You will need a separate exposure meter (or just guess) and a separate rangefinder (or just guess). They are cheap and a lot of fun, and the bellows seem pretty good, my 510 dates from 1936 ish and the bellows are in great condition. The early Novar lenses are not great, prone to flare but sharp in the centre, but that's part of their character. Lens hoods and filters can be hard to source. There are loads of other brands, lots of German ones, but it's worthwhile getting your hands on it and listening to the shutter, looking through the lens with a torch and checking the bellows are light tight by going into a dark room and shining a torch into them when they're fully extended. I find them quite addictive.
