There seems to be a minhag (or at least what appears to be a minhag) that children who deliver mishloach manos are given a small sum of money by the recepient.
Is this an actual minhag?
And if so, what is the reason for it?
I've heard this money being called 'אויס לייז געלט', meaning 'redeem' money. So it seems that a child may have wanted to keep the mishloach manos for himself, or maybe in the spirit of purim acted as though he expected something from the recipient or else he will not give it but just keep it. So in the spirit of Purim that every request and every demand is legitimate to make someone else happy, we go along with this for simchas Purim. Or maybe it's without the actual,threat element, just that how can you take candy from a child without giving something for it, when after all the child has the technical ability to not hand it over in the first place. Obviously this can't be given by the giver, because the giver is handing over the goods, so how can you threaten them to say 'I won't take it unless you give me something'?