Greed or need: Why gas is cheaper in some parts of metro Phoenix?

• I drove 2.5 miles north and saw another QT charging $4.50. The Mobil across the street on McKellips Road and Country Club Drive was charging $5.25. What gives?

State of play: According to the National Association of Convenience Stores, gas stations, even those within a few miles of each other, often have different wholesale costs.

• Larger stations may be able to buy in bulk, bringing down their cost per gallon.
• Some stations are on more expensive corners than others, so they make up their real estate costs with higher gas prices.
• Stations may also carry different brands. Fuel that carries the name of a major refinery tends to cost more.

Yes, but: Sometimes, pricing is purely a business strategy.

• For instance, if a station is near the airport, right off a highway or in an otherwise convenient area, the prices will likely be higher because the owners know you're going to pay it.

Tips and tricks: GasBuddy is a popular website that shows the lowest gas prices in each ZIP code.

• After listening to radio ads about Upside for years, I finally downloaded it, and now I love it because it shows me gas prices near me and offers cash back at many stations.