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.
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
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 a yearly “review” right before school year. Raise allowance as appropriate. If they want more money, they’ll have to take on more responsibilities.
Take the family on periodic “spending fasts.”
As an exercise, go a day, a weekend or a week without spending any money. Make due with what you have.
Encourage participation. Tie in spending fasts with holidays, lent or in support of a cause.
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.
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!
There are things you should not say:
Never comment or ask a woman about her age or weight.
Never comment on how many kids someone has (or doesn’t have.) The size, timing, composition, etc of someone else’s family is not your business to weigh in on. You never know who is struggling with loss or infertility, etc. And if someone announces they are expecting their seventh kid, the only correct response is “Congratulations” “How are you feeling?” etc. Just like you would if it was their first. Never ask someone how much weight they lost. If they’ve lost weight, just say “You look wonderful/amazing/ fantastic, etc.” And of course never comment on anyone having gained weight. Just say “You look wonderful.” And never never never ask someone how much money they earn or how much money they have, or how much they owe or paid for something, etc. People’s finances are personal, and are just not any of your business.
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.