A mile or two from our house, there is a Mobil service station that will check your tire pressure and also sells the least expensive gas around. A young man wanders by, as you give your car a transfusion, and asks if he can test your tire pressure. If it is down, he shoots in the necessary amount of air. There is no charge except for whatever your heart tells you his services are worth.
Because I always accept the pressure check offer, the tires are wearing evenly. Instead of an address, this place should provide a map where X marks the spot.
Treasure is in the eye of the beholder.