Manufacturers - unless they sell the goods they produce to end-customers - benefit from coupons only indirectly, through retailers. Retailers, however, can benefit significantly from this marketing strategy: Various studies show that businesses that send coupons to their customers via email can have a 48% increase in revenue. Coupons increase customer loyalty, and, as we’ve already learned from the coupon statistics above, online shoppers who use coupons spend 24% more than shoppers who don’t use them.