Have the ability to pay merchants from a Pot you create.
Do you shop at Tesco all month, create a Tesco Pot, place your budget in there and anytime you make a payment to them it takes out from the Pot.
Same for other merchants, car parks etc
This means you can create a monthly shopping budget, car park budget, petrol budget etc and keep it separate from your main account.
Also it would be great if you had AI to analyse the Pot and your spending and as the monthly progresses it tells you if it thinks your spending it too quickly estimating that you will run out of money in your Pot for that merchant.