The provisions of sections 325D.30 to 325D.42 shall not apply to a sale at wholesale or a sale at retail made (a) in an isolated transaction; (b) where cigarettes are offered for sale, or sold in a bona fide clearance sale for the purpose of discontinuing trade in such cigarettes and said offer to sell, or sale shall state the reason thereof and the quantity of such cigarettes offered for sale, or to be sold; (c) where cigarettes are offered for sale, or sold as imperfect or damaged, and said offer to sell, or sale shall state the reason therefor and the quantity of such cigarettes offered for sale, or to be sold.