You've got a Werra I, made by Carl Zeiss Jena circa 1955. I know it's a I because it has a simple optical viewfinder and no meter; you'll probably be annoyed to know that there also were a Werra II, with framelinedand meter, and a Werra III and IV which had coupled rangefinders and interchangeable lenses; the III was meterless and the IV had the meter
They also were available with the leatherette either in black, like yours, or olive drab. Which shutter does yours have? Some came with Compur-Rapid or Synchro Compur, but you'll also see them with Soviet-bloc East German Prestor RVS shutters; the latter can be distinguished by the shutter's 1/750 top speed, a trick achieved by using double-ended blades that only had to rotate in a single direction rather than opening, reversing and closing as with a normal leaf shutter. (Brilliant Marxist ingenuity? Maybe, but the Kodak Synchro-Rapid 800 shutter worked on the same principle.)
Nice for you is that your camera appears to be in very nice condition, the Tessar lens should make nice sharp pictures, and your Werra came with its neat reversible lens hood/shield that protects the lens and shutter mechanism when screwed big-end-first into the cocking ring surrounding the shutter mechanism.
And before you kick yourself too much for not having snared one of the RF-coupled models, keep in mind that their rangefinders are curious split-image-only items somewhat like the one found in the Soviet Leningrad -- the central rangefinder spot is NOT semitransparent, it's opaque and shows only the view through the tiny RF window. The system is bright, all right, and the rangefinder patch is nicely defined, but since you can't see coincident images, you can only focus accurately on objects having well-defined vertical lines! It doesn't say so in my reference books, but I'll bet the framelines are like the Leningrad's, too -- black etched rather than white reflected or projected. I recall looking through a Werra at a camera show a few years ago and being impressed by the finder's brightness and clarity, but it's still a bit peculiar.
What's it worth? Sorry, no idea, but it says in my long-outdated McKeown book that the III and IV models are fairly common in Germany, less so in the US. There's an olive Model IV from Slovakia currently languishing on eBay under a $90 starting price with no bids, but its condition doesn't appear to be as nice as the one you've got, and there's a lot to be said for the purity of the uncluttered Werra I even if it's not a rangefinder camera!