Start “home economics” school with them. Laundry, cleaning, cooking, how to change a diaper, comfort a baby, soothe a toddler, what's involved in caring for pets, budgeting for food, keeping track of maintenance schedules for humans, pets, cars and machines. Engage with guests, be a good host, etc. Know when and how to tell someone to GTFO of the house (racist or misogynistic speech, etc.) Every kid needs to learn the art and science of home management. Look for and point out examples in books and movies of good home science skills.
There’s always a temptation to throw money at your problem. But remember there’s nothing you can buy that will make up for what is really needed. And the stuff that accumulates while you try to fix the problem just ends up being a problem on its own.
***Manners!! *** Etiquette is the secret sauce. Everyone appreciates being treated with respect. Etiquette is the art and science of respecting others. It’s timeless and universal. Customs change, hence the need for constant study, but respect is always the foundation. In summary: Be nice. Start with yourself. Study etiquette. It will help you in every single interaction you have, social, professional, financial, everything. Manners apply to every human, in every interaction, even on the hard days. Hence, the need for practice.
Check out from the library or Amazon: “My First Money Book: A Guide for Parents and Children to Saving, Spending, Sharing, and Investing Your Money” by Reggie Nelson
I once asked my mom if my grandmother (her mother in law) was rich. Her reply: “No, but she likes to think she is.” I think she meant my grandmother spent money like she had plenty of it when she really did not. Can relate. I hope you do better!
IMPORTANT: If you borrow money from someone pay it back as soon as possible. In full. If you borrow an item, return it in excellent condition. I’d say if you borrow a car, return it with a full tank of gas but hopefully by the time you’re driving there won’t be any combustible engines. So return it fully charged!
Have a yearly “review” right before school year. Raise allowance as appropriate. If they want more money, they’ll have to take on more responsibilities.
Practice “going without.” Talk about how nobody gets what they want all the time. We should learn how to just choose to go without something we want. Get them in on the discussion and pick something every day to do without.
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.