What's the Lesson of the Wishing Well?

I was sitting in a park with a fountain the other day and watched as a father gave his young sons coins to throw in the water. This started me thinking about what was being taught here.

The lesson might be that following a dream costs something. It might be that it's a lesson that teaches that doing what we want takes time and money and effort.

Does it teach that having dreams and goals is more valuable then money?
That money only works when it is used?

What do you think? What is the lesson of the wishing well?