Gasoline always was cheaper in NJ, even though full-service.
Then the state increased the tax on it. Now the price is about the national average.
I traveled through there years back and it did not seem to be as cheap as in the south. But my main gripe was less about the cost and more about the hassle of dealing with a middle-man and the sheer nanny-state aspect of it. I remember thinking some mob deal must have foisted this upon NJ.
Of course if they didn’t force you to use full serv and have to pay those attendants salaries — it should be even cheaper.
Of course the state probably subsidizes the prices — thus the NJ taxpayer pays for the reduced price.