Collectibles are entirely based on that. In fact, I'd say they're defined by it -- if there's little chance of missing out on something, then that thing isn't a collectible. How big of a role this plays (and sustainably so) in other kinds of goods is less clear, although discount sales are exactly about creating this kind of fear -- or, conversely, rare opportunity -- and they do work. Regularly scheduled sales, on the other hand, work more by creating a price differentiation, where people to whom a product is worth less than the regular retail price can choose to wait.