How much money do you think a 6th grader can bring when they are in a field trip?

On field trips they don't generally purchase anything. The either bring lunch or the school provides it. He's going to be too busy doing stuff than to sit at the snack bar. I would maybe send them with 5 to $10 for a snack and a drink. But the snack bars usually aren't open during field trips

You can bring as much as you feel is needed, but i personally believe that $15-$20 is a good estimate on how much you would need for such things as drinks and food.