SALT LAKE CITY — The best deal on fuel in the country right now might be here in Utah, where people are waiting in lines to pay the equivalent of 87 cents a gallon. Demand is so strong at rush hour that fuel runs low, and some days people can pump only half a tank.

It is not gasoline they are buying for their cars, but natural gas.

By an odd confluence of public policy and private initiative, Utah has become the first state in the country to experience broad consumer interest in the idea of running cars on clean natural gas.

Residents of the state are hunting the Internet and traveling the country to pick up used natural gas cars at auctions. They are spending thousands of dollars to transform their trucks and sport utility vehicles to run on compressed gas. Some fueling stations that sell it to the public are so busy they frequently run low on pressure, forcing drivers to return before dawn when demand is down.

It all began when unleaded gasoline rose above $3.25 a gallon last year, and has spiraled into a frenzy in the last few months.

Ron Brown, Honda's salesman here for the Civic GX, the only car powered by natural gas made by a major automaker in the country, has sold one out of every four of the 800 cars Honda has made so far this year, and he has a pile of 330 deposit slips in his office, each designating a customer waiting months for a new car.

"It's nuts," Mr. Brown said. "People are buying these cars from me and turning around and selling them as if they were flipping real estate."

Advocates for these cars see Mr. Brown's brisk sales as a sign that natural gas could become the transport fuel of the future, replacing much of the oil the nation imports. While that remains a distant dream, big increases recently in the country's production of natural gas do raise the possibility of making wider use of the fuel.

To a degree, it is already starting to happen in Utah, where the cost savings have gotten the public's attention. Natural gas is especially cheap here, so that people spend about 87 cents for a quantity of gas sufficient to propel a car approximately the same distance as a $3.95 gallon of gasoline.