Imagine shopping online for a $100 pair of jeans and facing two ways to save. You could apply a single store promo code for 25% off, or you could combine a 10% retailer coupon, a 10% friend-referral code, a 3% cashback offer from a rebate app, and a 2% credit card reward.
Doing the extra legwork for the four-part deal does not save you any extra money, and if the retailer applies percentage discounts one after another rather than all at once, you actually end up paying slightly more. Yet a new study published in the Journal of Retailing finds that shoppers consistently prefer combined discount packages over single discounts of the same face value, largely because piecing together a multi-part deal makes buyers feel uniquely savvy.
Retailers like Target, CVS, and merchants on Shopify increasingly allow customers to combine promotions, while deal-sharing websites and social media creators routinely post tutorials on how to layer offers from different sources. Marketing researchers Wenting Zhong and Lan Xia of Bentley University wanted to understand what drives this enthusiasm for discount stacking.
Previous academic studies had examined what happens when stores offer two discounts at once, such as taking an extra 15% off an already reduced clearance item. Those earlier investigations concluded that shoppers prefer double discounts either because of pleasant surprise or because of bad math, since many people mistakenly add two percentages together without realizing the second discount applies to a smaller balance.
Zhong and Xia suspected something else was happening when shoppers combine three or four smaller offers from a mix of stores, credit card portals, and rebate apps. They proposed that as the number of discounts grows, shoppers stop focusing on mental arithmetic and instead evaluate the package as a personal achievement.
Testing the appeal of the stack
To see how stacked deals perform in the wild, the researchers first gathered data from Slickdeals.net, an online community where users share and rate money-saving offers. They collected 9,109 deal posts across eight retail categories, ranging from electronics and tools to clothing and groceries, and matched 5,299 comparable posts that offered similar total savings.
Across the platform, posts featuring stacked discounts were associated with much higher engagement than single-discount deals, and the advantage held up after matching comparable posts. On average, stacked deals drew 13,670 views compared to 8,219 views for single discounts, and they also received significantly more user upvotes and comments.
Because online bargain hunters might be unusually enthusiastic about complex deals, the researchers next ran a series of controlled online experiments with general U.S. consumers recruited through the CloudResearch Connect platform. In their first experiment, 473 participants imagined browsing an e-commerce site and were randomly shown either a single 25% store discount or a combination of two, three, or four smaller discounts—including email sign-up promos, credit card offers, and Rakuten cashback rebates—that added up to 25%.
Participants who were offered the stacked deals reported a significantly stronger desire to buy from the site than those offered the single 25% discount. When the researchers asked participants to estimate their total percentage savings, averages hovered between 24.2% and 25.5% across all four groups, showing that people were not being tricked into thinking the stacked deals were financially larger.
Instead, the experiment revealed a clear psychological chain of events. Combining multiple promotions made the deal feel rare and one-of-a-kind. This was partly because assembling it took more effort, and partly because participants felt they were extracting unplanned value that the retailer had not deliberately designed.
That sense of having secured a unique deal triggered what marketers call smart-shopper feelings—a surge of pride and resourcefulness. Feeling like a clever shopper, in turn, increased participants’ eagerness to complete the purchase.
The friction of too much complexity
Stacking discounts was not entirely frictionless, however. The same experiment showed that as more discounts were added to the pile, shoppers viewed the promotion as more complicated and mentally taxing to evaluate.
This rise in complexity chipped away at participants’ smart-shopper pride and slightly dampened their urge to buy. Even so, the positive rush of securing a unique deal outweighed the annoyance of doing extra mental work, leaving stacked discounts with a net advantage over single coupons.
To see how durable this effect was, Zhong and Xia ran four additional experiments testing different ways stacked deals can be structured. In a test with 440 participants shopping for Puma shoes, stacking three discounts beat a single 30% coupon whether the smaller promos were all percentages or a mix of percentage discounts and dollar-off coupons.
Another experiment with 349 participants showed that four stacked discounts outperformed a single coupon regardless of whether the offers were shown all at once on a single screen or revealed one screen at a time. A third test with 786 participants found that stacked packages boosted buying interest whether the discounts came entirely from the retailer, entirely from outside apps and credit cards, or from a mix of both.
Interestingly, participants viewed a mix of store and third-party discounts as less complicated than a stack of three coupons issued entirely by the same store. The authors suggest that shoppers may already be familiar with combining store promos with outside credit card or cashback perks, whereas juggling three separate rules from a single retailer feels more confusing.
In a fourth variation involving 446 people shopping for a Kohler showerhead, the researchers compared shoppers who had to actively hunt for three stackable discounts—waiting through simulated search screens and answering a feedback question—against shoppers who were handed the exact same three-part deal with step-by-step instructions from social media. Those who assembled the deal themselves reported higher buying intentions than those following someone else’s instructions, largely because reading and executing a stranger’s multi-step coupon strategy felt more complicated than discovering the pieces firsthand.
When a single big sale is enough
While splitting a modest promotion into pieces makes it more appealing, the researchers suspected this tactic might matter less when a store is already offering a massive markdown. Because typical retail promotions average around 20% off, a huge single discount already feels like a rare find on its own.
In their final experiment, Zhong and Xia tested this boundary with 604 participants by comparing a single discount against a four-part stacked deal at two different levels: 25% off and 65% off. At the 25% level, the four-part stack gave a large boost to how unique the deal felt and how eager people were to shop.
When the total savings reached 65%, the gap between the single discount and the four-part stack narrowed considerably. A flat 65% markdown already felt special enough to make shoppers feel savvy, leaving less room for a multi-part stack to add excitement.
This final experiment also tested whether stacked deals simply make people feel lucky rather than smart. While finding a unique stack did make participants feel fortunate, those feelings of luck did not drive them to buy; the urge to spend was driven by the internal pride of feeling like a skilled shopper.
Takeaways for retailers and shoppers
For businesses and marketers, the findings suggest that breaking a standard 25% or 30% promotion into smaller, combinable perks—such as pairing a site-wide sale with a loyalty program bonus or a referral code—can generate more excitement without costing the store extra margin. Retailers can also partner with cashback platforms and credit card shopping portals so customers can build their own multi-source stacks while third parties pick up part of the promotional cost.
At the same time, companies need to watch out for the headache factor. Many retailers bury their coupon-stacking rules deep inside fine-print policy pages, forcing customers to guess which codes work together.
If businesses actively show customers how to combine offers at checkout, they can preserve the thrill of the treasure hunt while minimizing the mental strain that turns buyers away. As for limitations, the researchers note that their controlled experiments relied on hypothetical shopping trips and capped the discount stacks at four items, meaning future field tests in live stores will be needed to find the exact tipping point where piling on a fifth or sixth coupon becomes too frustrating to bother.
