The Mobil Oil Marianas service station in Chalan Kiya displays its new fuel prices on Monday. Photo by Emmanuel T. Erediano From $4.30 a gallon, the regular gas price is now $4.40 a gallon. Mobilâs premium gas price went up to $4.85 a gallon from $4.75 a gallon while the diesel price went up to $4.58 a gallon from $4.48 a gallon. Shell Marianas is expected to follow suit. On Tinian, Mayor Edwin Aldan said the only gas station there has raised its price to $6.12 a gallon. He said changes in gas prices in the world market are beyond the control of the local government.