They play the 'limited-time offer' card.
Stores not only entice you with sales, but they also use limited-time offers to increase your sense of urgency in making a purchase.
Oftentimes, they're simply creating the illusion of an unbeatable sale — while these items may be tempting to buy on the spot, you're better off putting the item on hold, thinking through the purchase, and making sure it's really worth opening your wallet for.
Source: U.S. News & World Report