The value of anything is that which a willing buyer is willing to pay to a willing seller. Simple economics.
I do have, and use a mju-II, the back window fell out so it is taped over and I have to make a note of the film inside. I also acquired an Olympus IS-100, fixed zoom SLR 28-100 fully automatic for £5! Image quality is much the mju-ll. Bit of a lump but a nice camera too.