The Brief According to AAA, the national average price for a gallon of gasoline has hit $4 again. Texas gas prices have climbed back above $3.50 a gallon. Gas prices in Texas are on the rise again after the national average hit $4 per gallon. By the numbers:According to AAA, the average cost for a gallon of unleaded in Texas on Monday is $3.57. Although higher, Texas is trailing the national average by 43 cents.