DS, 6, is pllying in the park over the road with some schoolfriends and children from the street.
I am watching from the kitchen window. 
The ice-cream man has taken to comming daily since the nice weather began. I sometimes let DS have one but don't want to start the having one daily or expecting one as he come 3x a day in holidays.
Can't be bothered with the 'oh he's here can I have one' everytime I hear the fucking tune. 
DS is very good and accepts this (or has so far) 
So he came again (2nd time tonight) whilst DS in the park and DS comes over to me. I open the door expecting him to ask me again for one, but he says a boy has given him a pound and he's going to spend it on an ice cream.
I tell him he needs to give the money back and say 'thankyou', but that he can't take the money.
DS says OK and trots off again.
Please tell me I did the right thing, or AIBU as most the children got a lolly and this boy was probably just being kind to DS?? (boy is probably only 7 or 8 yo).
TIA