Blue water key is going to be a lot more then a campground in Kansas $200. might be a decent price in Bluewater where 20. might be more appropriate for Kansas.
Just to many variables to have a set price anywhere. I tend to frequent campgrounds by lakes most state or federal. They tend to be lower price and less crowded (except high demand times). I use PPA for campgrounds while traveling or boondock which saves money as well.
Jplante4 had a good point on property taxes. Where I have a seasonal their property tax doubled in one year, they had no choice except to pass the cost on to the customer.