It is actually a Chinese charm and not a coin. The inscription (bottom photo) reads "shui lu ping an" which literally means "may you have peace by land and water" or, more simply, "I wish you a safe journey". The reverse side (top photo) of the charm includes the following symbols: 1. Above the hole is a star constellation probably meant to be the "Big Dipper". 2. Below the hole is one of the "eight trigrams" which is kan and represents "water". (For more on the "eight trigrams" please see my web page The Book of Changes and Bagua Charms) 3. To the left and right of the hole are ancient weapons. Judging from the metal and patina, I would guess that the charm was produced during the late Qing (Ch'ing) dynasty (1644-1911). I am not familiar enough with prices to estimate its worth but I hope you find the above information helpful. Gary
Outside the Chinese-speaking world, these charms are very lightly collected. Gary will undoubtedly correct me if I'm wrong, but so far as I know there is no reliable catalog or price guide in published in English.
