From the age of about seven my dad used to make sure I had a fiver in loose change in a purse in my school bag, just in case I had to get the bus home. It was drilled into me not to spend it on crap, although I was precociously sensible.
My DC really don't carry money at all. I'm beginning to think they really should, although they have far less independence.
A fiver wouldn't go far these days though!