Admissible evidence

a. In determining "cost to the retailer" and "cost to the wholesaler", the court shall receive and consider as bearing on the bona fides of such cost, evidence tending to show that any person complained against under any of the provisions of this act purchased cigarettes and tobacco products, with respect to the sale of which complaint is made, at a fictitious price, or upon terms, or in such a manner, or under such invoices, as to conceal the true cost, discounts, or terms of purchase, and shall also receive and consider as bearing on the bona fides of such cost, evidence of the normal, customary, and prevailing terms and discounts in connection with other sales of a similar nature in the trade area or state. b. Merchandise given gratis or payment made to a retailer or wholesaler for display, or advertising, promotion purposes, or otherwise, shall not be considered in determining the cost of cigarettes and tobacco products to the retailer or wholesaler.