(1) I assume you are 62 or older. If so, be sure to spring for the $10 interagency lifetime pass from your nearest National Park or COE campground. It gets you free entry to those federal facilities that charge admission, and half-price camping at most of the campgrounds. Best $10 you'll ever spend.
I stayed at a beautiful COE park near Topeka a couple years ago, with the pass, a site with electricity was $9 a night. My favorite nearby National Forest Service campground (no hookups, but a dump station and water to fill your fresh tank) is $8 a night.
(2) Some states also offer similar passes/cards for state parks. I know Virginia does, although it is nowhere near as good a deal as the federal pass.
(3) I have found myself staying in some private parks for a night or three for as little as $20 a night, hookups included. You need to do some shopping around. $45 a night is easily beaten, just not necessarily at the closest park to where you are at the moment.