I bought gas this morning in Slater for $3.39 per gallon, but when I got to Ames, everyone was selling for $3.89 per gallon. Why does it cost 50 cents more per gallon in Ames? And why does every gas station (except Sam's Club) sell for the same price. I don't think there is a monopoly, but maybe it is as simple as informal price-fixing. Is there someone in Ames who sets the price and others follow?