A normal good is a type of thing that most people like to buy. It's like a toy that you really want and your parents can buy it for you. When you have more money, you can buy more normal goods. And when you have less money, you can buy less normal goods.
For example, if you like to eat burgers, burgers are your normal good. When you have more money, you can buy more burgers. But when you have less money, you can only buy one burger or no burger at all.
Normal goods are not like luxury goods, which are expensive things that only some people can buy, like a fancy car or a high-end vacation. Normal goods are like things that most people can afford and enjoy, like clothes, food, and toys.