I know your parents wont let you spend the money, but I really really strongly suggest you get:

It’s a very solid program and will help you achieve what you want to achieve.

cut out the sugar go powerwalking and lift weights you can make your own weights fill a bucket with water and lift arms alternately

Do lots and lots of sit-ups. That’s what I do and you could bounce a coin off my abs!!

If you can’t buy dumb bells, use canned food!

Speaking of food, I don’t mean to be offensive, but cutting out virtually all junk food snacks is terrific because then you won’t have to worry about burning off chips or anything. It gives you a great head start!

I would just type into google “simple exercises” or something.
eHOW or wikihow is really good, as well.
Good luck!

go buy dumbells from walmart for like 20 bucks.

use them religiously.