SDCL § 37-10-13: Tie-in sale at less than value of other goods deemed rebate or concession.

For the purpose of this chapter, a so-called tie-in sale of cigarettes, whereby in conjunction with the purchase of cigarettes, at a price which would not otherwise be less than cost to the vendor, the purchaser is offered other merchandise or other thing of value, without charge or at a charge less than the fair and reasonable retail value of such other merchandise or thing of value, such transaction shall be deemed a rebate or concession.