as a general rule, young men pay a huge price for insurance until they are at least 25. but actually, there is no way to even give a ballpark figure, because it depends on so many different things. like has he had driver's ed? where do you live? will he be on your insurance or on his own policy? also different insurance companies even in the same palce can have a huge difference in price for the same amount of insurance. just too many variables to give an answer.