I don't know a lot about coins except what I picked up trying to broker a rare Roman bronze one, once. The little I learned then leads me to suspect this one's stamped, probably Roman, probably rare, probably hard to identify or value. It might even be Roman Occupation somewhere, minted in a local mint. The recognizeable Pegasis on the reverse will help, and what might be a winged Mercury on the obverse will also help, whether it's a winged Mercury or a ruler. The symbols to the right of the profile will make it fairly unique, too.
I can't recall where I found them, but there are a number of sites on the internet where you can peruse scans of thousands of ancient coins until you find one that's similar, eventually, probably. But if it's as rare as it appears to be you might still have some difficulties valuing it.
This one looks awfully nice.