I'm still going for the gusle. Value? Not very much in money, I'd think (the skin is damaged and the neck looks warped) but such things are interesting in themselves, and the bow looks better than mine. I tried a cello string rather than the traditional horsehair; that gives a bigger sound, but still with a very limited dynamic range.

Photo, showing playing position: Gusle player

There are plenty more pictures out there. For a recording of the instrument in context, see Udovica Jana (The Widow Jana)