I have an M3 double stroke which I got from a portrait photographer/camera store owner before he closed up his retail shop. He'd used (and serviced) it himself and I saw photos he'd taken with it. It's missing a bit of vulcanite which I can live with (this camera has had a life!).
I find it tricky to load. I already had a Konica rangefinder I'd used quite a bit, which took some getting used to when I bought it; I find rangefinders quite different than using SLRs. I ended up getting a digital camera that uses the same Leica M mount that also works with a Voigtlander rangefinder I have, so the lens itself was worth it.
I can't remember how much I paid, at least several hundred, and that was one heckuva bargain then.
This camera must be a doorstop or the current owner hasn't got a clue of the value.