This afternoon I have a friends teenage daughter watching my kids (2 and 4)so I can go to a funeral. It will be for 2 hours and kids will play or watch TV. 2 year old is toilet trained and independent. I have never used a babysitter before and the girl/her mum offered since she had finished her exams and just left school. I know the girl isn't expecting payment but I'm sure a token would be appreciated. I'm hoping £10 and a box of chocolates would be OK? Or should I give £20? I don't have a lot of extra cash but want to let the girl know that I appreciate the favour.