My daughter has her own, albeit small, part of our family budget. A typical third grader, she would like to buy out the entire Scholastic catalog she brings home from school each month. This year I gave her a $20 budget for the entire year to spend on books only (otherwise she would blow it all on the gimmicky toys the company likes to hide among the literary offerings).
At first she balked, but now she manages her allotment wisely. Only one book has so far made the cut into her $20 stash. She still has $17 left to go. I think the experience is making her a smarter shopper. Now, she analyzes each purchase she makes--at least out of the book catalog.
At the mall, it's a different story.