I spotted this today incongruously amidst a shop's as of yet unsorted material, the only ancient in there. The Pegasus motif made me think right away in terms of an issue of Corinth, and in fact that's what it turns out to appear to be, cataloged I believe as BMC 448.
Diminutive in size at 11.5 to 12 mm in diameter, with the weight coming in at 1.44 grams. I don't see that a denomination is specified.

