Healthy Cooking as a Teenager with Limited Time!

I'm a teenager living with my dad. My dad typically never gets home until maybe 7 or 8 at night and I never really learned how to cook growing up. I'm always either out with friends, at sports practice, or working so I don't have much time to make a meal for me and my dad either. For months now, I have been living off yogurt, PB sandwiches, eggs, boca burgers, fruits, and raw veggies, but I honestly get sick of having the same things everyday. I can't really afford to go out and take cooking classes so what is the best way to learn?