I don't know Nick....IMHO, since the kid is really young and probably wouldn't appreciate any of the gifts you thoughtfully give him... I would just buy him a cool toy for <$50 and then stick the rest in a savings or trust for when he can really appreciate (hopefully) the cash.
Let's see... (depending on how creative you are with money, it can even be more)
If you put away $150 X 18 yrs. (ie., for a trust)= $2700 + @ approx. 4% interest = approx. $2808.... hmmm, looks like a down payment for his own car or bike. :dance: