Why do American prices always end in .99?

American stores end most prices in .99, like $9.99, $19.99, or $24.99. This is called charm pricing, and it has a simple goal: to make a price feel cheaper than it is. Studies show that shoppers' brains read $9.99 as “nine dollars and something,” which feels much smaller than ten. The pattern started in the late 1800s, partly to make sure cashiers had to open the cash register and give change, which kept staff honest. Today the trick still works, even though everyone knows it.

In this clip, a man plays a shopping game where he’ll buy items if the price is under a set number. Almost every price ends in .99: $15.99, $7.99, $24.99. He laughs at how close some are to his limit.