When it comes to gas prices, most stations are branded—meaning the name of a major oil company hangs out front—and must buy gas from their proprietary company. They can’t shop around. With a lock on sales, the oil companies charge each station a different price depending on various factors, such as the station’s competition and its location. That means a station can pay as much as 46 cents a gallon more than one down the street, and that cost gets passed along to you.
Faced with such instability, Gainesville, Fla., resident Steven King plans ahead: “If I know I’m going out of town, I try not to buy gas so I can fill up after I leave.” King says he can save 10 cents a gallon by purchasing gas on the road. You’d be similarly wise to shop around—with prices constantly in motion, the cheapest gas may not be at the same station every time.
Above is an excerpt from the book "1,001 Things They Won't Tell You," which was published in May 2009 and highlights popular columns from SmartMoney's long-running "10 Things" feature.