S.C. Code Ann. § 12-36-70 — "Retailer" and "seller"

"Retailer" and "seller" include every person:
(1)(a) selling or auctioning tangible personal property whether owned by the person or others;
(b) furnishing accommodations to transients for a consideration, except an individual furnishing accommodations of less than six sleeping rooms on the same premises, which is the individuals place of abode;
(c) renting, leasing, or otherwise furnishing tangible personal property for a consideration;
(d) operating a laundry, cleaning, dyeing, or pressing establishment for a consideration;
(e) selling electric power or energy;
(f) selling or furnishing the ways or means for the transmission of the voice or of messages between persons in this State for a consideration. A person engaged in the business of selling or furnishing the ways or means for the transmission of the voice or messages as used in this subitem (f) is not considered a processor or manufacturer;
(2)(a) maintaining a place of business or qualifying to do business in this State; or
(b) not maintaining an office or location in this State but soliciting business by direct or indirect representatives, manufacturers agents, distribution of catalogs, or other advertising matter or by any other means, and by reason thereof receives orders for tangible personal property or for storage, use, consumption, or distribution in this State.
(3) operating as a marketplace facilitator, as defined in Section 12-36-71.
The department, when necessary for the efficient administration of this chapter, may treat any salesman, representative, trucker, peddler, or canvasser as the agent of the dealer, distributor, supervisor, employer, or other person under whom they operate or from whom they obtain the tangible personal property sold by them, regardless of whether they are making sales on their own behalf or on behalf of the dealer, distributor, supervisor, employer, or other person. The department may also treat the dealer, distributor, supervisor, employer, or other person as a retailer for purposes of this chapter.