Yes, you do not have to be a member to stay there. But as a member, you get a 10% discount off your stay. Fees are $24/year. Due to the cost of staying at KOA, you can recoup your membership fees back quickly. They also have a rewards system where you earn points.
KOAs are open to anybody. The membership is basically a discount program. For 20 something bucks a year you get 10% off regular rates when you stay at a KOA. Your stays also accumulate points towards discounts as well.
Gotta figure out if you are gonna stay at one of their campgrounds often enough for the 10 percent savings to outweigh the membership fee. For us we have to stay more than 2 weekends before any 'real' savings kick in.
2012 Koala 25DS
2011 F150 Ecoboost SuperCrew with Max Tow Package
We always more than break even at KOA's. In some areas it's the best choice for full hookups, which we like. You accumulate points and can use the points for discounts on future sites. Some KOA's charge extra for things so always ask. For example, we use our own satellite TV rather than pay extra for their cable.
Lonny & Diane
2004 Country Coach Allure 33' "Big Blue"
Towing 2008 Chev Colorado 4x4