Spending money on trips

Since it is my policy that all “required” expenses, food, lodging, entertainment entrance fees, etc are paid by the group I point out in advance that all expenses are paid. A youth can go on the trip without any money and not miss a thing. How we fund the trip differs from trip to trip: fees, fund-raising, whatever. This allows quietly giving scholarships (“stipends” as I called them because that hasn't the negative connotations “scholarships” has) on the sly without anyone being the wiser.
However, I also will mention if there will be opportunities to spend money (there may be shopping available).
I avoid entirely discussion about how much spending money a kid should bring. That is way too dependent on the individual circumstances of youth and their families.