Gas prices in Arizona are down about a cent on average this week. Triple-A Arizona says the average price of gas in Arizona is $2.28 a gallon this week. In Flagstaff, gas prices are up two-cents a gallon on average to $2.38 a gallon. Some stations are selling gas for $2.29 and lower. In Prescott, gas price remain unchanged this week at $2.32 a gallon. Some stations are selling gas for $2.19 and lower. Officials say a small increase of demand pushed gas prices up a little in areas this week.