My wife is given a  personal allowance each week which she can freely spend on anything she wishes or save it for larger items, it is her personal money and she does not have to account for it.

Then she is given the family money for food , clothing etc, which she must spend wisely and I do like to see shopping lists the night before she goes shopping.  She is totally accountable for this money and at any time she must be able to account for every penny by showing receipts and the remaining amount.
At no time must she spend this money on herself without first getting my approval.

Next she has 24/7 access to our bank account which contains what we call rainy day money, to cover emergencies should she break down in the car or encounter another crisis that needs emergency funds.
Other than that she is not allowed to spend any of this money and she is trusted not to be tempted by new shoes, clothing etc.

She knows exactly what the punishment for over spending is and there is never any chance of getting out of it.
Part 1: She is spanked for the over spending which is  a minimum of 6 hard hand slaps on her bare bottom, followed by 1 hours corner time and then she will kneel in front of me while  I explain why keeping to budget is important.
Part 2: She is then on the next Sunday evening given a caning for each  pound (UK money) she has over spent if this is over £20 the remaining punishments are given the following Sunday/s until we reach the total.
I can assure you this is a very effective punishment and it is always a long time till she next over spends.