How much is a handgun permit in green oak township MI?

Statewide there's none, some localities have a small nominal fee. Generally from what I've noticed in my area on the county level it's rare, but on the municipal level (any city, village, or township with their own police) will have the chance of a $5 or $10 fee. The best thing you can do is call or stop in your local police station and ask. A lot seems to depend on how rural or populated the area is, as well as the general feeling about firearms in that area.