Coupons can be placed inside packages so that customers cannot redeem them quite as quickly. This encourages repeat purchases.
The coupons are called coupons by an item being scanned on the register.
The coupon being delivered is often for a competitor's product, thereby which encourage brand switching the next time a consumer maker a purchase.
To encourage purchases of additional product, sometimes manufacture provide cross-ruffing coupons, which is placing a coupon on one product for another product.