commercial document, commercial instrument - a document of or relating to commerce

book token - a gift voucher that can be exchanged for books costing up to am amount given on the voucher

luncheon voucher, meal ticket - coupon redeemable at a restaurant and entitling the holder to a meal

twofer - a coupon that allows the holder to purchase two items (as two tickets to a play) for the price of one

sample - a small part of something intended as representative of the whole