How to make some extra cash at a young age?

My daughter wants to make some extra money and is only 13. She doesn't want/need to fundraise. Just some easy money.

When I was that age I used to offer to walk peoples dogs for money, I would put up posters around my neighborhood. I also used to offer babysitting service for small animals, like if someone was going away I would take there rabbit/hamster/bird/etc for the weekend or however long and look after them. I made a fair bit of money for a 13 year old doing this. Once my mom ordered about 50 iPhone cases off of eBay for cheap and helped me sell them on Kijiji, she would go with me of course for safety reasons, we sold them for $5 each, she let me keep what ever profits were left after I paid her back for the original cost. It taught me some entrepreneurship skills too, and its something you guys get to do together.

Babysitting or yard work. I know it's cheesy but she could always bring out the old lemonade stand!