It all depends on the cost per kilowatt hour and your use of appliances like the AC or convection microwave.
With no AC use we used about 300 to 350 KWh per month.
It was always cheaper for to stay for a month and pay for metered electricity no matter where we were in the country.
We have seen KWh rates from 11 cents per KWh to as high as 20 cents per KWh.
In spite of what some think, there are states that allow RV parks to charge more for electricity than they pay. AZ is one that does. It is not a Federal matter, it is governed by state utility boards and regulations.