For children, - Charity Stories: Joy of Charity

Once a companion of the Prophet Muhammad (S) called Saad had gone to
the battle field outside Medina. On the way, Saad heard that his
mother who had been sick had died. Saad who loved his mother very much
came to the Prophet Muhammad (S) and said that he had wanted to give
charity on his mother's behalf but it had not been possible for him.
Saad then enquired if he could give charity on her behalf now that she
was dead. Prophet Muhammad (S) replied in the affirmative. Saad then
went on to inquire what was the best charity he could offer. Prophet
Muhammad (S) said that on the route to the battle field he had seen
that the soldiers were thirsty and there was a dire need of water.
Prophet Muhammad (S) suggested that the best charity was to dig a well
on the road so that caravans would benefit from the supply of water
and it would also be a continuous form of charity for years to come.
That was what Saad did.