I love the upper campground very much. It's about 12 or 17 dollars a day though. But I feel like leaving my stuff there and not the side of the road is better. Lower campground is good too. Dont get me wrong, i just prefer the upper.
You only have to pay if you stay in one of the two designated campgrounds, and as Kyle said the Lower campground is the only one currently open. There are lots of unofficial campsites along the stream on the side of Poplar Stump Road as well as White Oak Gap Rd at Raven Cliffs that are no charge.