Because of inflation, the prices of things will go up - a dollar will buy less today than it did years ago. The price of most everything will be higher in the future. For example, if there’s something you want to buy soon, inflation won’t affect the price of your goal very much. But if you have a larger, longer-term goal - like saving for college - inflation may increase its price. It’s smart to invest for your longer-term goals so that your money might grow faster than the rate of inflation.
Look at the chart below. Ask an adult what lunch cost when they were your age.