Have you ever gone shopping with your parents and wondered why some things cost a lot of money and some things don't? Everything you see in a store or online has a price tag on it, and that price tells you how much money you need to pay if you want to buy it.
The price of everything depends on a few things. The first thing is how much it costs to make the thing. For example, if someone wants to make a robot toy that can talk, they need to buy parts like wires, batteries, and speakers. Those parts can cost a lot of money, depending on where they come from and how many are needed. So, the person who makes the robot toy has to decide how much they want to charge for it, based on how much it cost them to make it.
The second thing that affects the price of things is how many people want to buy it. If a lot of people want a toy robot that talks, then the person who makes it can charge more money for it because they know people will be willing to pay more to have it. But if nobody wants a toy robot that talks, then the person who makes it might have to lower the price or not make it at all because they won't be able to sell it.
The third thing that affects the price of things is competition. If there are other people or companies who are making the same thing, then the person who makes it needs to compete with them. They might lower their price to try to win customers away from the other people who are making the same thing. Or, they might raise their price if they know their product is better than the competition.
So, in summary, the price of everything depends on how much it costs to make, how many people want it, and how much competition there is. When you see something with a price tag on it, remember that it wasn't just made up randomly. Someone decided how much it was worth based on these factors.