Several years ago, I wrote a book called Clark Smart Parent, Clark Smart Kids in which I discussed the art of giving an allowance. And it is an art, definitely not a science. Trying to figure out how best to use an allowance to give kids a sense of responsibility and motivation is a challenge that nobody has the right answer to, only opinions.
I have a bias toward allowance as a paycheck that is earned for doing chores. The typical allowance for a kid is now $15 a week, though it's nowhere near that in my house.
My thing is around age 5, when a kid is old enough to understand, you can consider an allowance. I have given my kids a dollar a week according to their grade level as long as they complete their chores. The chores are detailed for them on a chore wheel so everybody knows what they've got to take care of.
But you have to find what fits your kid. I met with someone recently who was designing a high school curriculum about personal finance. That made me think about talking with my 12 year old about what things cost, including a car payment, a home payment and taxes. The thing is, it has to be an ongoing dialogue.
For younger kids, I love the three jars concept that came out of the Christian fundamentalist movement. Each jar is marked with a red, green or yellow heart. One jar can be used to hold money for charity; another jar holds money for current spending; and the third has money for longer-term savings. This provides a very simple, clear and tangible lesson for children.
It is my belief that an allowance up to age 16 is more about discipline and responsibility with a kid than it is about teaching the value of a dollar. The point at which you can teach a kid about the value of money is as a junior or senior in high school.
As for Clark Smart Parent, Clark Smart Kids, you can find my book ultra-cheap used or get a signed copy at ClarkHowardStore.com.