Help! What It's That?

Sorry, bit it doesn't have anything to do with the Danube River. It's a rechenpfennig, or German counting-token. Most, like yours, were made in Nuremberg. The token-master named on this piece is Johann Albrecht Dorn, master from 1732 until his death in 1783. Yours is a "sun-moon-and-stars" type, listed at the bottom of the list of classes on the UKDFD reference site.

Value? Hard to say; since they're not coins, they're not listed in the coin catalogues. The coin dealers in my country are just guessing when they put a price on them. I've seen prices range form $5 to $50.

Rechenpfennigs were made in Nuremberg, but sold all over Europe, and even further; they've even found them in the ruins of the earliest colonies in North America. Anyone who needed or wanted a bunch of coin-like objects, for whatever purpose, might buy Nuremberg jetons, because they were cheap and plentiful. I imagine this would have been the case even in Bulgaria, which was still part of the Ottoman Empire at the time this token was made.