S.C. Code Ann. § 58-23-620
No city, town, or county in this State shall impose a license fee or license tax upon a holder of a certificate A or a certificate B, and no city, town, or county shall impose a license fee or license tax on the holder of a certificate E or a certificate F, Certificate of Compliance, or a common or contract motor carrier of property, except the city or town of such carrier's residence or the location of his principal place of business. However, the fee required of a holder of a certificate C is in addition to any license tax or license fee charged by a municipality.