Gas prices hit $4 in all 50 states for the first time, national average reaches record high --California has the highest gas prices at more than $6 a gallon | 17 May 2022 | Gas prices continued hitting record highs this week, as the average gallon of gas now costs at least $4 in all 50 states for the first time ever, according to the auto club AAA. Just three states - Georgia, Kansas, and Oklahoma - hadn't crossed $4 a gallon on Monday, but they all saw jumps on Tuesday to hit that threshold. Kansas still has the cheapest gas in the nation at $4.006 a gallon, while California has the priciest at $6.021 a gallon.