How much to give your adult children financially?

Hi to everyone from the United States. I am a Swedish dad and I know that the financial tradition in my country is very different from yours. I have two children, one 4 years old and one 3 years old. I would like to know how much money adults normally gift their children as they grow up financially. For example, if a child wants a new iPhone, how much do you pay and how much does the child pay? If the child wants to buy a car, what is the amount that parents resemble to pay to their children?<br><br>&#x200B;<br><br>PS. Sorry for my English.