The cost was $12 per person. To take a closer look, $5 per person for a bus ride. Like a school bus, but with only 10-12 rows of seats. (It truly flashed me back to my school days riding a metal bus with bouncy seats). The driver was very informative and interesting. The tour included a brief history (with pictures) of how the Crazy Horse sculpture became fruition.
Along with seeing the sculpture, there is a beautiful, fairly large museum filled with artifacts, artwork, and history.
An expansive gift shop filled with local artists' sculptures, paintings, etc, along with the usual t shirts_hoodies, magnets, and postcards. All were reasonably priced for a gift shop, IMO.