Pay Less at the Pump

Before you hit the road, change your engine's air filter and make sure your tires are properly inflated. "A clogged or dirty filter can decrease your gas mileage and underinflated tires can cause excess drag because more rubber hits the road," says Karn Jilek, a Jiffy Lube car-care expert. Check your owner's manual to see when you should replace your engine's air filter and for your vehicle's proper tire pressure. Right before you leave, check gasbuddy.com to find the gas station in your area - and near your destination - with the least expensive gas. And fill up the night before you leave: According to Wallner and Matisic, gas prices tend to go down after regular working hours.