The best supps of all: more food, water, sleep.
But then, you didn't tell us what your goals are, where you're at right now, etc. You're still growing, so many people would say you don't need supplementation. Supplementation is just that: supplementation! Get your food nailed down first.
There are tons of articles here that'll show you what to do. Check out the beginner's threads by Vroom (I think Vroom wrote them; someone correct me if I'm wrong).