Just like that, gas price changes at the pump.

Byline: Karen Miller

Sept. 13--You pull into a gas station to fill up your tank when, out of the corner of your eye, you catch a funny sight -- the red LED lights of the gas sign changing prices. The LED lights jiggle like a slot machine hitting the jackpot. And magically the price of a gallon of gasoline has gone up or down in price. Who does that and when does it happen? Usually the action is quite simple: The manager of the station tells the employee to key in the new price and a couple of buttons get pressed and the sign is changed, said Patrick J. DeHaan, senior petroleum analyst at GasBuddy.com. The same goes for the pumps, only different buttons. But …