boost it to what it is at the pump. In CA they have almost $3 a gallon taxes. It has gone up, maybe to $2.50 a gal. (excluding state and local taxes) But don't forget who you are paying. In AZ and AR the state excise tax is about $0.25 a gallon, as is the federal excise tax, another $0.20-0.30 a gallon. Texas is about a dime cheaper for both combined. *This is compared to "red farm diesel" which is devoid of the taxes. Too hard to find gasoline comparisons directly, they don't want you to know. But I know they have "red farm gas" too. A BIG fine if you get caught using it in a road vehicle.
In CA they must have a Sin tax, Climate tax, privilege tax in addition...