S.C. Code Ann. § 39-7-40: Sale below stipulated price constitutes unfair competition.

Wilfully and knowingly advertising, offering for sale or selling any commodity at less than the price stipulated in any contract containing either of the provisions mentioned in Section 39-7-30, whether the person so advertising, offering for sale or selling is or is not a party to such contract, is unfair competition and is actionable at the suit of any person damaged thereby.