We have a budget of $100 per kid and try to cut down from that each year. Ultimately after it is all said and done, I typically spend around $125 on the two older ones and around $80 on the 2 year old. Not trying to be unfair, it just turns out that her desires at 2 are much less money than the older boys wanting electronics and such. Needless to say, every year they are inundated with TOO MUCH. I always get frustrated that I did that to them, they forget the whole reason we are celebrating. Argh!
$200 seems a bit much to me, I would just pick one big item (around $50 to $75) then do a few small items after that (around $5 to $15) and hit the Dollar Store for stocking stuffers crud. Ultimately your son will end up with anywhere from 4 to 6 gifts plus stocking stuff. Then when you figure in gifts from family which will probably work out to be another 4 to 6 gifts - GOOD GRIEF - that is up to 12 gifts in less than 24 hours!
I think he will be more than satisfied with that amount of stuff, not to mention the fact that he will not be bored.
Good luck and have a wonderful holiday!