It is easy for you to create partner coupons that you can allow aggregators to distribute!
Create new traffic to store by allowing others to treat their customers with your coffee. The end-consumer may get the coffee free, but the gifting party or the aggregator distributing the coupon pay for it.
Aggregators may be digital market places like deal aggregators. Other aggregators are serving a different purpose. These may be using your everyday relevant products as digital rewards to their users either directly (do X to get a free coffee) or by allowing their users to use points they have earned over time.
Encourage your supplier brand partners to use digital coupons that consumers can redeem in your stores in any aggregators they see relevant.
