There is Crossroads - very fun (sky hike! great barn!) for children but more pricey, though we got our money worth out of our Mountain Membership. It can also be crowded at some times, especially festivals. Weekdays will be easier to navigate.
There is a lot of free stuff beyond that. There is a playground (contrary to a previous review from someone who apparently couldn't read the free map they give you..), a museum, of course- the LASER SHOW, the walk up trail to the amazing views at the top of the Mountain, the grist mill and covered bridge, running/bicycling paths, nature paths... Well suffice it to say, there is a multitude of things to do. Of course, it is nature. Go to any park and if you don't like nature, you'll be paying more for touristy things.
The area has a rich history. (Only the uneducated and ignorant would think the racist history is the extent of it - it was there, as in most of the South, actually most of the country, but it is far from the complete story.)
There is much about geology to learn.
This is also the largest exposed body of granite in the world. (To the previous reviewer - I have a tree in my back yard. That doesn't mean the Taigan Forest is irrelevent.) There is a lot more to it then that, too.
Going informed might improve your experience, but for anyone, it is a fun time.
I have been going since I was a child, and now take my own child. I teach her and play with her - we have picnics, we hike, etc. We spent yesterday at Snow Mountain, which is a rare chance for her to see snow in Georgia!
I trained for many races on the multiuse pathways. (and ran some races here that the ATC puts on!)
This is a true jewel in Georgia. If someone can only visit one attraction in GA, this is it.