I know what you mean by the rising cost of camping, but I think this is still the lowest cost method of taking a vacation or get away for the weekend.
Try taking a weekend at a resort of some type instead of camping. I would bet that your cost for the weekend would be double or more then the camping weekend cost are.
Another thing we do to keep our cost down is try using COE camp grounds. These are federal parks that are maintain by the Core of Engineering for the US government. Most of these parks have water and electric at their sites and some even will offer full-hook ups. Sites are level and will except most 5er or motor homes. If not the web sites will till you a large of a unit is permitted.
We stayed at Lake Powhatan in Asheville NC. a COE park with full-hook ups for $29.80 a night this June. Then is Nashville TN. we spent $20.00 a night for a site with water and 50 AMP electrical site another COE park.
Here is the web site that I will use to find COE parks.
http://www.recreation.gov/welcome.do?topTabIndex=Home
Another site I use is RV park Reviews to help pick the lowest cost park but yet one that we would be willing to stay at. Here is the web site.
http://www.campgroundreviews.com/
Jim