One that especially sticks out is when the Circuit City chain went under. I remember reading about how they brought in an outside company to handle the sales, and the first order of business was to raise all the prices on everything in the store. DVDs that they couldn't sale at $10 were suddenly flying off the shelves at $20 (don't remember the exact numbers).
It makes you realize what a fine line (which each person has to draw for themself) there is between clever marketing and slimy, manipulative tactics.