Go into the dealership armed with discount information. (CarMax photo)

Did you know that the absolute best day of the year to buy a car this year was, gulp, Christmas Eve (with a projected 7.25 percent average discount)? That's according to the useful (and free) information at TrueCar, which is dedicated to demystifying auto pricing.

Don't worry if you didn't buy a new car on Christmas Eve, by the way, because New Year's Eve is almost as good (7.04 percent). Six of the Top 10 best days are in December, so you might want to take a look before the calendar turns over.

The site is full of interesting information like that, by the way. The most heavily discounted 2009 sedan is the Saturn Aura (24 percent)-and that's because GM is dumping the remaining inventory before it kills the brand. For 2010, the Mercury Grand Marquis is the most heavily discounted (13 percent), and that's because its average buyer is eligible to receive Modern Maturity. The Corvette is the most heavily discounted coupe (18 percent), and that's probably because despite being the object of many a young man's lusts they don't sell all that well. Jeep's 2010 Grand Cherokee is heavily subsidized (15 percent) because Chrysler is a basket case right now....