My son wants to buy an Apple mobile phone, which is too expensive. How can I convince him?

It is too expensive for my son to buy an Apple mobile phone. We should persuade him to talk to him calmly. The child is at school, and the rebellious mentality is very serious at this time. Parents can't reject their children at once. They should convince people by reasoning. When a child knows his parents' good intentions, he won't ask for an Apple phone.