Thanks for all the tips. We ended up with a blue blazer,pair of dress pants2 shirts, a tie and a belt for around $250. Not great but not terrible either. We ended up finding it all at the Brooks brothers outlet. First stop we hit and when he found stuff he liked we went with it.
I figure we'll do a suit in the spring for jr. Prom(if he goes)
Thats not terrible actually. Brooks Brothers has great quality and if you felt like it, you could always resell those. Believe it or not, I think my son has finally stopped growing for a bit, so you may find you will get more use out of it than you think.