It is a great idea to be teaching kids this at a young age to be responsible with money and to teach them budgeting.
1) Establish the fact that chores are expected and not paid for, but then offer a choice of chores that can earn money. Example: making their own bed, as messy as it is is their own space = no pay
2) Pick up their own laundry, toys. = no pay
3) Empty dishwasher = paid
4) Tidy up mud room / shoes are at door way = paid
Next once you have establish the pocket money, you will need 3 jars.
3) Free Spending
Tax needs to be explained weekly so they understand it, you can decide ahead of time what to make of that money afterwards (a suggestion would be to donate it).