In establishing the cost of a given article, goods, wares, or merchandise to the vendor, the invoice cost of the article, goods, wares, or merchandise purchased at a forced, bankrupt, closeout, or other sale outside of the ordinary channels of trade may not be used as a basis for justifying a price lower than one based upon the replacement cost as of date of the sale of the article, goods, wares, or merchandise replaced through the ordinary channels of trade, unless the article, goods, wares, or merchandise is kept separate from goods purchased in the ordinary channels of trade and unless the article, goods, wares, or merchandise is advertised and sold as merchandise purchased at a forced, bankrupt, or closeout sale, or by means other than through the ordinary channels of trade, and the advertising shall state the conditions under which the goods were so purchased and the quantity of such merchandise to be sold or offered for sale.