One of my favorite episodes of Columbo is called Double Exposure, where Columbo uses subliminal tricks to help nab a marketing genius who murders a client using subliminal advertising.
Subliminal advertising is considered a deceptive business practice by the Federal Trade Commission, but in a column in Parade, marketing guru Martin Lindstrom reports on five subliminal but legal tactics that marketers use to lure you in: If something feels heavy, you'll be more comfortable buying it. Certain kinds of music makes you more inclined to shop, and made-up traditions lend credibility to brands.
My favorite example of this is the world famous Samuel Adams brand of beer. I was having dinner with some friends a few weeks ago and two of them ordered Sam Adams beer. I asked them to guess when the company was founded. They guessed 1790 and 1820. The real answer: 1985! It's named after a famous founding father who sidelined in beer-making but has no other connection to him other than the name. But it's been a magnificently effective marketing tool.
One way to avoid falling victim to clever marketing tricks is to do as much shopping as possible where you can comparison shop easily and not be lured in by a store's scent or music. Of course this isn't such a good idea for clothing, but it might be the best way to buy electronics.
Don't get tricked by (read this) subliminal advertising!