But if your job is secure and your financial house is in order, it is a buyer's market for cars.

Car sales are down a fifth to almost a third regardless of nameplate. Car dealers frankly admit they're more willing to dicker. With numbers like this, they have to.

Here's some counterintuitive advice. You'll save more trading your SUV or a station wagon, saving 10 miles a gallon, than trading your subcompact for a hybrid, saving 20.

This is because miles per gallon is a ratio, gallons per mile is your true burn rate.

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