How thick is a short board???
What kind of metal? Standing seam? Ribbed? Painted? Galvanized? Will the old roof need to be stripped? Disposal fees? How high is the job?
Any "features" such as dormers or valleys will add to the cost significantly.
Around NH something like $300 per Square might be ballpark for a simple installation. But it could vary widely.
You ought to get local estimates and they will reflect local styles, materials, and costs. Should be easy to do if you ask around in your area.
Pete