I imagine it's the same price nationwide at all Pemex stations

MH

I filled up my car the day of your post but did not pay attention to the price. But I filled up again tonight and here is your answer.

A liter of Magna (regular unleaded) is $6.92 pesos per liter. At the current local bank exchange rate of $10.15, this is $2.50 per gallon.

A liter of Premium is $8.64 pesos, or $3.23.

For the math challenged, multiply the per liter price by 3.8 to get pesos per gallon, since there are roughly 3.8 liters in a gallon.

Then divide that number by the exchange rate for buying pesos, or selling dollars, which is the same thing.