If you're thinking of trading your gas-guzzler in for a zippy little fuel-efficient car, beware: You might end up handing some of your gas savings to your insurance company.

Three of the government's top-ranked vehicles for fuel efficiency — the Toyota Prius hybrid, the Honda Accord and Toyota Corolla — also are on Insure.com's top 10 list of the most expensive 2008 vehicles to insure.

But insurance rates are complex, differing by state, by how and how far you drive, by type of car, crash history, claims costs. And in some cases, even a consumer's credit history.

Quotes gathered by the Deseret News on four of 2008's top-selling vehicles show rates could go either way in a gas-guzzler-to-sipper trade.

The bottom line, says consumer advocate Carmen Balber, is to get smart before you shop.

"If you're out in the market for a new car, certainly (look) at not only the fuel efficiency and ... cost of the vehicle, but how those insurance premiums stack up," said Balber, who works for the Santa Monica, Calif.-based group Consumer Watchdog, which pushes to have insurance rates based more on drivers' habits than their car types. "I think it's wise for all consumers to get quotes on auto insurance before they purchase that vehicle."

Fuel-efficient vehicles are hot sellers as people seek relief from gas prices, now exceeding $4 a gallon. As of last week, 101 customers had crowded onto the Mark Miller Toyota-downtown waiting list — up to nine months long — to get their hands on a Prius, the nation's No. 1 fuel-efficient midsize vehicle at up to 48 miles per gallon, staff there said.

Last week, as Miller debuted his "green" LEEDs certified, eco-friendly building, a first for a Utah dealership,— he was able to round up just one "green" car — a Highlander hybrid — for the showroom floor.

"Luckily," he grinned, "we have one in stock."

But will buying a Prius, or other fuel-efficient car, hike insurance rates? And by how much?

Last November, Insure.com, which aims to give consumers impartial insurance information, issued its top 10 most expensive vehicles to insure. It considered only top-selling 2008 vehicles.

The Prius was listed the third most expensive to insure, with an average premium of $1,210 a year, according to Insure.com.

The Honda Accord is the government's top-ranked fuel-efficient large car, getting up to 31 mpg. It's fourth on the most expensive list, at $1,203 a year. The Toyota Corolla, ranked second in the compact car fuel efficiency ranking, was listed as the sixth most expensive at $1,190.