From what I have read, most psychologists and other behavior experts agree that sales induce otherwise nonexistent demand. Generally speaking, when people see a product on sale or at a discounted rate, they are more likely to buy it then if it was at regular price… even if they don’t need it. And stores/companies sometimes take advantage of this behavior, such as how during Circuit City’s liquidation a few years back the company managing the liquidation actually marked up products over their regular price but said they were “on sale”. Then we have Rakuten.com (formerly known as Buy.com) who thinks shaving $0.99 off the price of a product is a great deal. Check it out:

Oh my God, what an amazing deal. I should run out and buy it right now. I think I’ll grab a copy for my grandmother, my aunt, my cousin, my nephew, and my neighbor’s dog. Because, you know, at this very low price this is a steal even as a chew toy.

[Thanks giopneo!]