I've seen answers saying its free and you can camp past the campground with numbers, but on another web page it says only designated sites and its $7. Could someone clarify?

It's all free. But the numbered spots are the only places to camp in that area. They call it the " wet lands" If you go past camp #15 you can camp ANYWHERE you want. Told to me by the local police dept. We camped out there for a week.

Suggested cost for the first campground with the picnic tables is $7. Further down there's a secondary campground, even more dispersed, with free camp sites.