Section 14M. No trading stamp company shall distribute trading stamps in the commonwealth or shall redeem trading stamps issued therein, unless each such stamp has legibly printed upon its face in cents or any fraction thereof a cash value as determined by said company. The said company shall, at the option of the rightful holder of such stamps, redeem the stamps in cash when duly presented for redemption in a number having an aggregate cash value of not less than twenty-five cents.