$50 is very generous. I'd give $50 and if he has expensive tastes, well, he can get a job and save up, like we had to in the olden days.

My family all give token gifts worth about a fiver for birthdays and Christmas. Kids are just as happy with something modest a lot of the time. This whole go for broke mentality that some people have - esp at Christmas when it can end up costing £1000s to buy for everyone - is crazy.