A gallon of gas costs about $ 2 in Tijuana ; it costs $ 1 north of the border . Watch Americans buying gas in Mexico » . AAA Auto Parts said short - term costs could spiral into long - term expenses . Mexican gas contains more sulfur -- which could hurt U.S. cars .
A gallon of gas costs about $ 2 in Tijuana ; it costs $ 1 north of the border . AAA Auto Parts said short - term costs could spiral into long - term expenses . Mexican gas contains more sulfur -- which could hurt U.S. cars .