That all depends on how responsible you are and what you're willing to do.
When I was thirteen, I walked dogs, cleaned yards, baby sat, ran errands and such. It's not a whole lot of money, but it's something.
It is too old for some things, old enough for some and too young for others.
I know that money expires in some countries in Europe. I had some old money (like 10 years old) and could not spend or convert it because it had expired. I found a website that converts expired money for some countries, but not all of the ones whose money expires.
you can do a lemonade stand,chores,garage sale, there are lots of things a 9 year old could do
i dono im 9 and i do chores and make bracelets to sell outside my house
they can sell candy and things in shcool.
one million years old
sell some stuff you dont need anymore.
The legal you have to be is 18 years old.
use your money properly
15 years old for college ,cars ,and all your graduation things and you should use compound interest i started when i was 10 and have made allot of money
24 years old
All things that are old are 100 years+ if they are antique