To say that the number of cities named Appollonia is misleading is a misnomer. Just within modern day Turkey alone there were nine cities with that name. This one was along the Rhyndakum River, and its coinage is very rare although interestingly inexpensive.
This particular Appollonia is believed to have been a colony of Miletos. A temple, predictably to Apollo, existed on an islet within the town. Although most of the ancient structures are no longer, a Byzantine citadel and city walls still exist.