Gas prices were up a bit on average this week across Arizona. Triple-A Arizona says prices at the pump rose three-and-a-half cents to $2.82 a gallon. In Flagstaff, the average price of gas was unchanged at $2.94 a gallon. However some stations are selling gas for $2.73 and lower. In Prescott, the average price of gas rose a cent to $2.99 a gallon. Some stations in Prescott are selling gas at $2.85 a gallon or lower. Officials say heading into the Labor Day weekend, gasoline demand remains strong. However, demand is chipping away at supply, but it’s not at a high enough rate to significantly impact gas prices. Triple-A says gas prices this weekend will be at their lowest in three years.