One point that isn't made in the article, only in the comments: never ever trade in your old car. Sell it yourself privately even though it's a pain in the ass. You will make at least a thousand more, and that's more than worth the trouble.
Car salesmen are trained to try and confuse you by repeatedly offering several different combinations of figures for new car price, trade-in price, financing, etc until you get confused enough that you take their offer. The trick is that they're keeping track of all their numbers on a sheet of paper, and they're making sure that no matter what combination they offer you, you're still getting screwed out of money. The process is aptly summarized at this Edmunds.com page.
When buying any car, you're always better off securing your own financing (best to do so through a credit union rather than a bank, they have lower rates), and to sell your trade-in yourself despite the hassle. Doing both of these can save you thousands.
I would also like to say at this point that you are almost always better off buying a lightly used car than a brand new one. Cars lose at least 10% of their value the second you drive them off the lot. Put 6 miles on a car and you're not going to get anywhere near back what you paid for it. A used car with less than 5k miles on it is as good as new provided the owner did the maintenance. So if you're serious about saving money, keep shopping around until you find the used car you want with low miles and whose owner responsibly kept all the maint records. It's a lot of trouble, but again, you will save thousands more.
And if you're one of those people for whom money doesn't matter and you can walk into a car dealership and buy a brand new car and get gouged to hell and not even care, I am officially jealous of you. Please remember me in your will. ;]
Oh yeah, getting back to the title of this entry... if you can imagine this same kind of stuff happening on a penny-ante scale, you get a pretty clear idea of what it's like to work at Best Buy or Circuit City or any of the other major retail electronics chains. I should know, I've been through that hell.