Car renters differ on prepay fuel option

— -- Car rental gasoline prices "are almost never a good deal," says John Clymer, a health systems consultant in Burke, Va., who rented cars for 30 days last year.

That's not so, says Kim Hunter, an executive recruiter in Los Angeles who rented vehicles 50 days last year. "My experience is the prepay gas prices are indeed lower than if I filled the gas tank prior to returning the car."

With opinions of frequent car renters mixed, and prices rising to around $4 a gallon nationally at gas stations, USA TODAY launched a survey to determine whether it's economical to buy gasoline from a rental company.

USA TODAY looked at renters' three options: prepaying for a tank of gas at a rental company's fixed price; refueling at a local gas station; or declining to prepay and returning a vehicle without refueling.

The survey found that filling the tank at a local station is usually the most economical choice. The average price at local stations is more often less expensive than rental companies' prepay prices. And motorists who prepay must buy a full tank of gas, even though they may not use all of it.

Prepay prices, though, may be attractive to renters unable to fill up before returning a vehicle. And they may be better for Enterprise Rent-A-Car customers. Enterprise's prepay prices at airports are usually lower than the average price at local gas stations.

Cost-conscious renters should avoid returning a vehicle without buying at prepay prices or filling up at a local station. They may be charged $9 or more a gallon if they leave it to the rental outlet to fill. That could mean $300 or more when returning a vehicle, such as a Ford E-350 passenger wagon, with an empty and very large fuel tank.

A look at eight companies

USA TODAY analyzed the gas prices of eight big car rental companies — Enterprise, Hertz, Avis, Budget, National, Alamo, Thrifty and Dollar — at 10 big airports on April 12 and compared them with average gas prices in local metropolitan areas on the same day.

The analysis included 156 prices charged by rental companies: 78 prepay prices and 78 prices charged by renters who don't prepay and return a vehicle without refilling the tank. Among the findings:

•The average price of gas at local stations was lower than the rental companies' prepay price at airports in 49% of all comparisons.

Car rental prepay prices were less expensive in 44% of the comparisons. Prices were equal in the remainder.

Cheaper average prices at local gas stations represent a turnaround from April 2011, when USA TODAY surveyed car rental companies' prepay gas prices at 13 airports. More than half the prepay prices then were lower than the average price at local gas stations.

•The biggest differences between prepay and average gas station prices were at Miami and Chicago O'Hare airports.

Avis and Budget were charging $4.23 a gallon to those who paid ahead at Miami — 23 cents more a gallon than the average at local gas stations.

At O'Hare, Enterprise Holdings' three brands, Enterprise, Alamo and Budget, were charging a prepay price of $3.79 per gallon — 52 cents less than the average at local stations.

The three brands' prepay fuel prices are "directly tied" to the average retail fuel price at local gas stations surrounding each airport, says Enterprise Holdings spokeswoman Laura Bryant.