Well when I was thirteen I discovered a webite called www.teenfreeway.com and you can win more than just money. you can win a variety of prizes, samples, and anything else.
by helping there mom and dad around the house or doing yard work or something like that u can always ask ur neighbor if u can mow there lawn for a few buck.
Chores, babysitting, I heard the Duggars (the people with 18+ kids) do a thing called "jurisdictions" and then pay a couple penny's for each jurisdiction you complete.
There are lots of ways. Such as: babysitting (you can make more if you get cpr certified), pet sitting and walking, tutoring, mowing lawns, watering plants, and doing chores around the house if your parents are willing to pay you.
My grandson is only 3 years old and he helps around the house, picking up sticks outside dumping the trash raking leaves shoveling feeding the pets mopping the kitchen floor. anything that needs done just ask and they are willing to help.