How much money does my son need to...?

If you give him �10,000.00, he won't need to work, and therefore he won't work. Depends on whether you want him to get the work ethic and be independent, or not. Just giving your children money is not always the best way, for their sakes. In fact, it seldom is. Your duty is to try to make him a sensible, responsible man, well rounded man. But of course you know that. Not an easy question to answer. Good luck.