Fourth of July travel could get a bit cheaper this weekend for Amazon Prime users who cash in an early Prime Day deal at the gas pump Thursday through Sunday. Amazon Prime members can get $1 off per gallon of gas at more than 7,

Twenty states boast average gas prices below $3, spanning from New Mexico to Missouri to South Carolina. Mississippi, the state with the nation's lowest gas prices, offers drivers an average gallon for $2.71. More than 61 million people are expected to travel by car over the July 4 holiday, AAA forecasted.

For once, gas prices may be a relief for the more than 61 million travelers expected to drive for the July Fourth holiday weekend. GasBuddy has projected a national average of $3.15 per gallon, the lowest in four years.