Every vehicle should have a fire extinguisher. If a car fire happens, you have maybe a minute or two before the vehicle becomes a total loss, since oil, gasoline, and plastic are extremely flammable. There simply isn't enough time to wait for a first responder to arrive.
Fire extinguishers come with different classifications, and the ones that apply to vehicles the most are Class B (flammable liquids) and Class F / K (cooking oil or fat).
This firefighter recommends Purple K extinguishers for vehicles. They're more expensive, but it may be worth it.
Most fire extinguishers claim to be refillable. However, if an extinguisher has a plastic head, most refill places will discourage you from refilling it due to problems. The best solution is to buy a refillable extinguisher with a metal head from the beginning.