7. Don’t wait! Only one left — the power of FOMO

One of the most effective ways to influence customer behavior is to create a sense of scarcity — a phenomenon known in behavioral science as “FOMO” (fear of missing out). A message saying “only one item left” can push a customer to make an immediate purchase, rather than saving the product for later and comparing prices elsewhere.

A great example of this tactic in action is booking.com. After entering your location and travel dates, you often see a message like: “Only 3 rooms left at this hotel!”



This kind of message creates urgency — we want to book quickly so we don’t miss out. At the same time, we assume the hotel must be in high demand if it’s nearly sold out.

This works perfectly in the hotel industry, where it’s easy to believe that availability is truly limited. But what about retail? No one believes that a supermarket only has 3 bottles of apple juice left every time — the urgency just feels fake.

To solve this, retailers can use **purchase limits** instead — for example: “Limited offer — max 3 cartons of eggs per customer.” On one hand, this creates a sense of scarcity. On the other, it smartly uses the **anchoring heuristic**, just like we discussed with strikethrough prices. The limit suggests that buying more than 3 is normal — setting 3 as the “starting point” in the customer’s mind. As a result, even if someone doesn’t buy all 3, they’re more likely to grab 2 instead of just 1.

In summary, it’s worth creating a sense of product scarcity. You can do this by showing limited stock availability or by introducing quantity limits — both of which may subtly encourage customers to buy more.