Start a yearly “review” right before school year. Raise allowance as appropriate. If they want more money, they’ll have to take on more responsibilities.
Beware that when you’re first exposed to a new thing: a car, a college tour, house, etc. you will feel AMAZING and totally seduced by the shiny newness. Be cool. Remember that glitters is not gold. Things don’t need to be perfect and even if the house is it doesn’t mean life will be.
Work on developing a “no shortcuts” mode. Looking for a faster/easier/bare-minimum option isn’t always bad. People get paid a lot of money for creating efficacy. But there are times when that approach is wrong. Anything you want to grow from (relationships, school, work, wealth, health, knowledge, etc.) those things deserve your full effort, focus and dedication. Play. Definitely play! But don’t f*ck around.
Check out the Jesuit Volunteer Corp. A short but deeply meaningful immersion into service, faith in action, selflessness and living on a lot less than you think you need.
Change is scary. But scary doesn’t equal bad. I don’t know what it’s going to look like but I know you will figure it out. You’re going to be okay no matter what curveballs you’re faced with. Stay calm. Be kind and respectful to everyone and every thing, including (especially) yourself. xoxo
Start saving money early. Save as much as you can.
There are plenty of things worth spending your money on, but be mindful about your money - Don’t p*ss it away.
Have them sort change, and eventually to count it. It teaches them to gather things that are alike, it's an introduction to money and it occupies them for 15 minutes! Just make sure they're old enough to be past the point of putting coins in their mouth.