Gap Risk

You just bought a new Xbox today for $500. Tomorrow you go back to the store and see the same console now for the price of $300, but there's no sale going on. The price just randomly dropped.

You made the risk to buy the game console yesterday when the prices could have changed unknowingly without anything causing the prices to change. The $200 dollar gap is the risk you took in purchasing the gaming console a day earlier, even though there was no way to know the prices would go down.