merchandise certificate; trading stamp
A certificate or stamp issued by a retailer that can be exchanged for goods, similar to a gift certificate or trading stamp. Often used in promotional contexts.
See also: 商品券
This merchandise certificate can be exchanged for any item you like at participating stores.
昔は商店で買い物をすると商品切手がもらえた。
In the past, you would receive trading stamps when you shopped at stores.