How old does someone need to be in order to start donating to charities?

You can donate to a charity at any age. Even if you don't have money to donate, you can donate items you no longer use such as clothes, toys or games in good condition.
You can also donate your time, however, charities may have restrictions on how old you have to be to volunteer or that you have to have an adult with you or have to have parent/guardian permission.