SDCL § 37-10-11: Purchases outside ordinary trade channels not considered in determining costs.

In establishing the cost of cigarettes to the retailer or wholesaler, the invoice cost of such cigarettes purchased at a forced, bankrupt, or closeout sale, or other sale outside the ordinary channels of trade, may not be used as a basis for justifying a price lower than one based upon the replacement cost of the cigarettes to the retailer or wholesaler in the quantity last purchased through the ordinary channels of trade.