How Can I Increase my Testosterone Level?

I’ve been reading a lot about gynecomastia and how it’s usually caused by low estrogen and testosterone levels. But i’m a VERY healthy person. I play soccer, 16 years old, 6′0 156 pounds or so. But everything i seem to eat doesn’t help it at all. I don’t have enough money to get surgery, and i don’t know how else to help the gynecomastia. Helppp