Interesting you should say that, because when it comes to budgeting, the “money experts” usually recommend that you dispense a set amount of cash, allocate it to each area of expenditure you have (groceries, travel etc), put that money in separate envelopes and stick to spending only that for a set period of time (like a week). 
Having said that, i hardly ever have cash on me, i use my cards WAY too much, and at the end of the month when the credit/debit card statements arrive, i have no idea when i spent what. People could do credit card fraud on me and i wouldn’t notice 
My tip: Rely less on public transport/cars (it does add up) and walk more. It’s healthy and it costs nothing!