Drivers in Illinois are paying a bit more for gas this week, but the cost to fill their tanks is less than last month. GasBuddy.com's latest report over the weekend said the average price for a gallon of unleaded in the state is two dollars and 49 cents. That's about nine cents more expensive than last week, but 14 cents cheaper than last month. Drivers in Cook County are paying the most at two-65 a gallon. Drivers in southern Illinois' Wayne County are paying the least at two-15.