Byzantine? | Late Roman City Commemorative

Not quite Byzantine, but it does commemorate the city of Byzantium (Constantinople).

It's from the series known as city commemoratives, from the late Roman period (around the time of Constantine the Great). The obverse is a personification of the city of Constantinople, reverse shows Victory on the prow of a ship, holding spear and leaning on shield. Click on the above link to see lots of varieties of coins like yours, differing mainly in the mintmark which sadly seems to be mostly missing from yours. Something like this one.

It's hard to judge condition from a modern scanner, but it doesn't look too good, with quite a bit of the obverse legend missing as well as the mintmark. I'd guess less than $10 for that one.

Wildwinds is an excellent site for identifying ancient coins. Particularly useful is the partial inscription search - simply type in whatever letters you think you can read, and it shows you all the coins on file with matches in parts of the legend.