As parents, we are responsible for teaching good stewardship to our children, no matter what their age.  As children get older, and their need for cash increases, their responsibilities should also increase.  Give them an opportunity to earn more money from increased chores, or by finding a part-time job.  Whatever the arrangements, you should always stress the importance of spending less than they earn.

First, teach them to tithe.  In addition, encourage them to consider giving additional offerings if they feel led to do so.

Second, teach them to save 10 percent of their income. They can set a number of goals for this savings, such as clothing, a car, or even college.

Finally, teach them to "live on" no more than the remaining 80 percent. They can keep the amount in each category separate by establishing checking and savings accounts, or by having a separate envelope for each category.

Once this is done, you should give them specific expenses they are responsible for.  For example, you may provide them with a used car and related maintenance, and they are responsible for gas, cleaning, etc.  If they want a nicer car, they can save for it.

You may want to also involve them in a limited number of family budget decisions.  This will help them understand that you are not "made of money" and live on a budget as well (hopefully this is the case for you).

Most importantly, help them understand that it all belongs to God, and when we are faithful stewards in even the smallest of incomes, He blesses us.  When this concept is learned and applied, they will be well on their way to becoming responsible stewards the rest of their lives.