'Cash for clunkers' ends today, so you've got to get your rebate now

Cars in junkyard

It's a hit.

But it will end at 8 p.m. EDT tonight.

Public response to what's officially called the Car Allowance Rebate System, or CARS, has been so enthusiastic that the $3 billion Congress approved for the program will be gone.

That means you've got only a few hours to get $3,500 or $4,500 for your old, gas-guzzling car or truck when you trade it in for a new vehicle.

The big question is whether the car or truck you have, and the car or truck you want to buy, qualify.

Here are the basic rules:

A major goal of the program is to replace cars that get poor gas mileage with ones that get better gas mileage. That's why the difference between the mileage of the clunker you're getting rid of and the new vehicle you're buying determines the size of your rebate.

Your new car or truck must get at least 4 m.p.g. better than your old one.

If the difference is between 4 m.p.g. and 9 m.p.g., then you'll qualify for $3,500.

If the difference is 10 m.p.g. or more, you'll get a fat $4,500.

The rules are a little different if you're trading in a pickup, sport-utility vehicle or van on a similar vehicle.

For small pickups, SUVs and minivans (which are considered Category 1 trucks in the CARS program), the traded vehicle's fuel economy cap is the same as for cars, 18 m.p.g.

But if you're buying another Category 1-type vehicle (trading a clunker minivan for a new minivan, for instance), the new vehicle only needs to get 20 m.p.g. to qualify for the program.

If it gets 2 m.p.g. to 4 m.p.g. better fuel economy than your old truck, you'll qualify for a $3,500 rebate. If the difference is 5 m.p.g. or more, you'll qualify for a $4,500 rebate.

Category 2 trucks are mainly full-size pickups and vans.

If you have one of those, you don't have to worry about the 18 m.p.g. cap. They're all eligible for the program.

But if you're replacing an old Category 2 truck with a new Category 2 truck, the new one has to get at least 15 m.p.g. and deliver a 1 m.p.g. improvement to qualify for the $3,500 rebate and a 2 m.p.g. increase for the $4,500 rebate.

To determine whether it makes financial sense to take part in this program, you have to know how much your car or truck is worth.

Edmunds.com or Kelley Blue Book provide good estimates.

If you take the rebate, you're essentially selling your old car or truck to the government, and it is supposed to be taken off the road and scrapped.

You don't get the rebate and its trade-in value from the dealer.

But you can accept a CARS rebate and benefit from any rebates or discount financing the manufacturer might be offering.

The CARS rebate should be deducted from the vehicle price after manufacturer incentives are applied.Just go to a participating dealer (most will be certified to participate in the program, but ask to be certain) and cut the best deal you can.

The dealer will deduct the applicable $3,500 or $4,500 rebate from the price, and you turn over the keys to your beloved clunker.

It's that easy.

One final thing: You don't have to do anything on the Internet to qualify for this rebate.

There already are numerous scams trying to steal personal information by claiming to "register" consumers for a clunker rebate. Ignore them.The National Highway Traffic Safety Administration is in charge of the CARS program and has created a Web site called www.cars.gov to answer questions.