Yes you are niave!
Teenagers eat their body weight in food every day. They grow out of everything in a few weeks, secondary school uniform for two (one of everything only) cost me upwards of 599 quid - and they have the audacity to outgrow it halfway through a term !!! kicking a football around involves transport, kit, home subs, away subs, food on the go (in addition to the huge meal they had before they left and the ginormous bowl of cereal they will eat on their return) not to mention all the extra washing from said activity. Oh and you had better hope they aren't any good at it because if they excel there are the extra sessions, competitions, more matches.
The cost of clothes and shoes when your 13 year old is 6ft tall. Oh and the products needed to de-zit and de-fuzz a 15 year old who needs a shave before school.
And if you think state school is free then think again! Equipment, books, extra curricular activities, sponsor stuff, lunches, cookery lessons, school trips, the list is endless.
And a that is before the family stuff, birthdays, Christmas, rewards, pocket money, leisure stuff.
But what I can't understand is how people can't know this stuff already?