S.C. Code Ann. § 59-31-320: Contracts with publishers for general depositories.

The State Board of Education may require all publishers of textbooks with whom textbook contracts have been made to maintain a joint agency or depository, in some city in the State to be located at some suitable and convenient distributing point, at which general depository each textbook publisher shall keep on hand a sufficient stock of books to supply the requirements of the State and through which central depository all textbooks shall be distributed. Any person or school not controlled by the State may order books from the general depository, and the books so ordered shall be furnished for cash at cost plus actual expenses.