In all advertisements, offers for sale or sales involving two or more items, at least one of which items is cigarettes, at a combined price and in all advertisements, offers for sale or sales involving the giving of any gift or concession of any kind whatsoever, whether it be coupons or otherwise, the portion of the dealer's combined selling price relating to cigarettes shall not be below the cost of the stamper, cost of the retailer or cost of the wholesaler, as the case may be. Other merchandise offered for sale as a tie-in with the cigarettes shall not be sold at less than the cost of the other merchandise nor shall the gift or concession of the other items advertised or offered for sale be used as an inducement to purchase cigarettes nor shall any payment, openly or in secret, of any rebates, refunds, commission or unearned discounts, whether in the form of money or otherwise, or secret extensions to certain purchasers of special services or privileges not extended to all purchasers upon like terms and conditions be made or offered as an inducement to purchase cigarettes.