And, as Melinda Murphy reports on The Early Show, some have found a unique way to run their cars that costs practically nothing.
Dave Kandell is one of them. His car runs on grease — used vegetable grease, that is.
Instead of heading for the gas station when it's time to fill 'er up, Kandell makes the round of restaurants in Huntington, N.Y., picking up used fryer grease he gets for free.
Sal Pagnotta, who owns Rosa's Pizza, admitted that when Kandell first asked him for the oil, "I thought he was crazy. I thought he was lying to me!"
Even Kandell's mom wondered if he'd gone a little nuts.
"I thought," Bea Kandell told Murphy, "he is probably taking a lot of time that he might be able to do other things with that might be more profitable."
After a pause, she added, "But now, maybe he's onto something!"
He just might be, Murphy said.
Wally Little owns a service station called Wally's Super Service, and has converted hundreds of vehicles to guzzle grease instead of gas.
"We've had kids in their 20s and people in their 80s come in; doctors, lawyers, restaurant owners, construction workers," he said.
One catch, though, is that only cars with diesel engines can be converted to switch between diesel fuel and veggie oil, creating a hybrid of sorts. They use the diesel oil to warm up the veggie oil.
Little charges $2,000 to $5,000 for his work, depending on the size of the car.
He says his grease-car conversion business has gone up almost 20 percent since the recent spike in gas prices.
And not only do they save you a lot of money, grease-cars are better for the environment than vehicles that use gas for fuel. The engines create very little pollution, and they offer a way to recycle used fryer grease. Some people even convert their cars as a way of making a political statement.
Lee Michel is a believer who calls himself "a knight who says nee." N-E-E — novelty, economy and the environment.
"On my last tank," he said, "I got 180 miles per gallon."
Aside from its limitation to diesel engines, veggie oil has other "buts."
Having a so-called "greaser" car is, Murphy said, a hassle. Besides picking up the oil, you have to filter it if you don't buy fresh oil.
As Kandell told her, "One chicken wing (that passes through the filter) can really ruin your day!"
And, Murphy noted, there's one thing you can't filter out: the smell.
She noticed Kandell's car smells like french fries!