Section 14F. Any retailer who, with intent to injure competitors or destroy competition, advertises, offers to sell or sells at retail any item of merchandise at less than cost to the retailer, together with any sales taxes or excises levied or imposed upon such merchandise by the commonwealth or the United States of America not already included in the invoice or replacement cost to the retailer, or any wholesaler who, with intent as aforesaid, advertises, offers to sell or sells at wholesale any item of merchandise at less than cost to the wholesaler, together with any sales taxes or excises levied or imposed upon such merchandise by the commonwealth or the United States of America not already included in the invoice or replacement cost to the wholesaler, shall, if the offender is an individual, be punished by a fine or not more than five hundred dollars or by imprisonment for not less than one month nor more than one year, or both; or, if the offender is a corporation, by a fine as aforesaid. Evidence of any advertisement, offer to sell or sale of any item of merchandise by any retailer or wholesaler at less than cost to him, together with any sales taxes or excises levied or imposed upon such merchandise by the commonwealth or the United States of America not already included in the invoice or replacement cost to him, shall be prima facie evidence of intent to injure competitors or destroy competition.