A campground that owns and reads the meters will charge whatever they want per KWH.
Not so. Every one of the 50 states regulates the sale of electric power and businesses other than electric utilities are not allowed to re-sell power at a profit. They can recover their costs for reading meters and billing, but they cannot arbitrarily set the kilowatt rate above what they pay.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL