If you plan to be among the 41+ million Americans expected to travel for the holiday, you may want to fill your gas tanks as soon as possible. AAA says gas prices have risen by two cents since Monday and six cents over the last week. The average price nationwide is $2.73. In Missouri, the current average is $2.43. The cheapest gas in the lake area is in Camden County where the average is $2.37 a gallon. Morgan County’s average is $2.39. Miller County is the most expensive with an average price of $2.43 per gallon.