I think it might be time for pocket money! Mr 13 is a big boy now and they do start getting independant.

My DD gets $20 per week, she has to feed cat, tidy room and unpack dishwasher 'cos she lives here. She pays for her own bus/rail ticket for the week about $11, so there's a bit over if she forgets her lunch or wants to get fish n chips with her GF's.
She has learnt to save it to buy movie tix etc. and is pretty savvy with it.
When she baby sits the kids she gets a bit extra, or I buy her a hair dye or something (she is 15 ).

There was actually a stage when she didn't get pocket money for months on end 'cos she kept forgeting to feed the cat. Now she never does and I'm usually borrowing money off her as I never carry cash!

Hey I just had two young boys at the door offering to mow the lawns or do weeding, I'm so darn impressed I'm going to get them to come back and do the driveway - their rates are very reasonable. They left a card with their mobile numbers and they are both 13!

Anyway JMHO!