SDCL § 37-10-2: Sale at less than cost to prevent competition unlawful--Rebates and concessions not applicable to other merchandise.

It shall be unlawful and a violation of this chapter for any retailer, wholesaler or other person with intent to injure competitors or destroy or substantially lessen competition,

(1) To advertise, offer to sell, or sell, at retail or wholesale, cigarettes at less than cost as defined in this chapter, to such a retailer or wholesaler, as the case may be, or

(2) To offer a rebate in price, to give a rebate in price, to offer a concession of any kind, or to give a concession of any kind or nature whatsoever in connection with the sale of cigarettes, if such rebate or concession offered or given in connection with the sale of cigarettes is not offered or given by the wholesaler or retailer in the same ratio with respect to all other merchandise as to which such rebate or concession may lawfully be given which is sold by such wholesaler or retailer in the ordinary course of his trade or business.