Your best bet at a young age to make money off your hobbies like selling coral on cl and fb market place, maybe finding a good deal on some fish and flipping them online with your allowance or Birthday money
If u like music or musical instruments invest in instruments like guitars basses, keyboards effects processors at pawnstores and then turn around and sell them online
If you have a grandma mom aunt dad uncle or grandpa that's into plant propigating house plants and flowers is a renewable way of generating revenue from practically nothing
U can use food scraps like the cabbage core tomato seeds strawberry seeds avocado and mango pits cherry seeds lettuce core garlic onions celery re root them in water then sell online for a couple dollars
If u like trading cards invest in baseball mtg, yugioh or pokemon cards and sell them online or locally
This is how I made money as a preteen/teenager until i was old enough to become a farmhand for my moms friend then when i turned 15.5 i got a work permit and started working at dq 16 hours a week on weekend that was in 2005