1. Coupon stacking boosts savings by using multiple coupons on one item.
2. Retailers benefit from increased brand awareness and customer loyalty.
3. Shoppers maximize savings during shopping trips with coupon stacking.
4. Downsides for retailers include reduced profit margins and delayed purchases.
5. Shoppers may find coupon searching tedious and risk overspending.
6. Costco does not accept manufacturer coupons but offers other ways to save.
7. Paying with a rewards credit card and using rebate apps can stack savings.
8. Price adjustments within 30 days can also lead to additional savings at Costco.