Gas prices are inching up across Arizona. Triple-A Arizona says the average price of gas in the state is up a half-cent from last week to $2.32 a gallon. In Flagstaff, gas actually fell a half-cent to $2.52 a gallon on average. However, some stations are selling gas for $2.39 a gallon and lower. In Prescott, gas was up a cent-a-half to $2.48 a gallon. There are some stations there selling gas for $2.21 and lower. Officials say unexpectedly strong demand and higher crude prices are driving prices higher in some cities.