BACTRIA: Heliokles I, ca. 145-130 BC, AR tetradrachm (12.91g), Bop-3A, BAΣIΛEΩΣ HΛIOKΛEOYΣ ΔIKAIOY; diademed, draped, and cuirassed bust right, wearing crested helmet covered with pelt of scales // Zeus Nikephoros seated left, holding winged Nike, who in turn holds a diadem; smoothing in the fields and edge to remove corrosion, VF, RR.
The normal tetradrachm of Heliokles I has radiate Zeus standing, holding thunderbolts and long scepter (Bop-1); from the records on CoinArchives, Bop-1 seems to be about 20 times more available than this type (Bop-3).
Estimate: 400-600 USD