- RENTAL CAR AGENCIES MAKE VERY LITTLE MONEY ON THE RENTAL ITSELF. A lot of the rental companies will try to keep the fares down to get you to rent and look at them. They make money though on refueling charges, insurance and also when you go over the mileage that was set. So they will probably be looking for other ways to get you too. Refilling your own tank is a way to save and also maybe trying to get unlimited mileage would be a good idea.


