Lots of taxpayer-funded county or municipal fire/rescue or EMS providers charge for ambulance transportation.

Typically, there is no charge if they don't actually transport you. Often, billing is handled by private contractors who are paid a percentage of their collections. They can get aggressive.

Some fire departments may charge for certain services. Crash rescue calls may be billed to auto insurers, and some fires are also being billed, depending on the cause. Around here, some law enforcement agencies are even billing non-residents a fee for their services at motor vehicle collisions (not to mention the inevitable citation, a.k.a. "ticket")