Gas prices in Arizona continue to fall. Triple-A Arizona says the average price of gas in the state is down a cent this week to $2.78 a gallon. In Flagstaff, gas prices are down slightly from last week to $2.74 a gallon on average. However, some stations are selling gas for $2.57 a gallon and lower. In Prescott, gas prices are down three-and-a-half cents from last week to $2.86 a gallon. Some stations in Prescott are selling gas for $2.84 and lower. Officials say lower crude oil prices and high gasoline stocks have led to lower prices at the pump.