soft billing

[atrea1]

we are a small rural fire dept located in N MN in a tourist area. Due to 90% of our fire protection area (275 sq mi) is Federal, State or Native American Trust Land and city being under 100 persons we do not have any tax base. We were3 wondering on soft billing to make up lost money because 80 percent of our calls for first responding (no ambulance) or fire suppression is for tourists or summer residents. We do not want to cause hardship on the residents who live here because we are a poverty area. We would forgive those who could not pay but wonder if we could legally bill our services to insurance companies or medicare and recover some of our costs. What would a MN dept charge for just responding to a call or doing fire suppression or defibrillation. Any help would be appreciated.