I'm more than a litte hazy about where the giant slide was. It was definitely in the West Columbia/Cayce area. If I had to guess, I would say it may have been on Airport Blvd near what's now the I-26 interchange, but it could have been further out on the Charleston Highway.
At any rate, it was clearly an economic boondoggle which didn't last more than a single season, which was a real shame. The way I remember it, it had a large number of sliding "lanes", possibly as many as a dozen. You would get a piece of some sort of fabric to slide on, possibly a carpet patch, or a burlap sack, walk the stairs to the top, pick a lane, get on your fabric and slide down. The whole thing was built on a metal frame, and I think the lanes were fiberglass. I have the vague impression that different lanes may have had different colors. I don't remember the price and whether it was "per ride", a time limit, or per visit. At any rate, it wasn't so exorbitant that my parents wouldn't take us.
As I say, it didn't remain a going concern for very long, but it sat there, defunct for at least several years. We kids didn't quite understand the concept "out of business". The slide was still there, surely if we kept going, eventually we would catch it when it was open. Our parents, I'm sure, rolled their eyes and tried to get the concept into our minds, but eventually every time we were in Cayce for Sunday dinner, they would give in to our pestering and drive us out to the slide afterwards. I can't remember exactly when the slide was finally torn down, but I think it was gone by the Tricentennial.
In the comments, Jaby Baby says the slide was called The Magic Carpet and was on Airport Blvd. Thanks Jaby!