We filled up a couple of jerry cans with gasoline (essence) at the French-side service station, Cadisco on Friday. The liter price has gone up from $0.79 to $0.82 (they use a one-dollar to one-euro exchange rate, rather then the current 1.4 rate). I roughly calculate this as $3.15 per gallon.
Can't complain as it is over a dollar per liter on the Dutch side.