Some people live simple for it's own sake. I'm starting to appreciate a simple life myself. But others (perhaps most of us) are choosing to live simple because of the impact it can have in other areas of our lives, such as to build for an early retirement so as to enjoy life on our terms, rather than live in the moment as slaves with lots of nice trinkets. Anyway, trying to impress these facts on someone who hasn't had life experience could be challenging. But kids are pretty smart. If you are on track for an early retirement, I would share that goal, and how you are working towards it. Teach them the value of compound interest, and how, over time, you will have more money, while if you'd spent it on a trinket, it would be gone, and the trinket forgotten. They may not respond to that, but keeping it on yourself, as James says, seems to be the best approach, in my eyes. Once you turn someone off, it's pretty tough to undo that. Once they understand the value of a dollar, you can give an example of a financial goal they can consider. Now retirement is too far off for them to probably care about (at least with societies definition). But getting started in life isn't. So I'd run the numbers to show how skipping little needless expenditures can lead to the down payment for a home. Or even a car, which is probably more appealing at this point.