We have an ice cream social every year funded by our parent group. We do not charge, since over half of our school is on some sort of assistance.
Our school has approximately 350 students. We go through approximately 12 pails of vanilla ice cream in 90 minutes and serve up approximately 300 bowls with 1-2 scoops each.
Tip: Let the ice cream sit for 1/2 hour before starting to scoop - otherwise, you'll get carpal tunnel from scooping rock hard ice cream.
2-3 ADULT volunteers are continuously scooping, and we have the school's scout troop or the local politicians/school board come in and dole out toppings (approx. 8-10 people).
As for how much rootbeer, you'd have to see what kind of cups/glasses you'll be serving them in and figure out how much rootbeer / per scoop you'll dole out. Will you be giving them straws or spoons?
(sounds very sticky to me!) I hope you're on good terms with the school custodian / kitchen staff.
We will be having a Family Night in the late spring. I wouldn't mind selling rootbeer floats to offset the costs. First off, how much vanilla ice cream and 2 lt. rootbeer do you think I would need for say 300 people? Secondly, how much would you charge, knowing that we want to make a little bit of profit? I know I came to the right place to ask these questions.