Purchase or make your own carnival tickets. Using tickets -- as opposed to each individual stand accepting cash -- minimizes the chances of cash mishandling. Charge one ticket for kiddie games such as a duck pond or lollipop pull. Charge two tickets for older kids' games such as a ring toss. Charge three tickets for activities such as a moon bounce. Charge four tickets for food items such as hot dogs and hamburgers.
Label each game, activity and food item with its ticket cost. Make sure the signs are easy to read.
Set up one or two ticket booths where participants can buy tickets singly or in bulk. Sell tickets for as little as 50 cents a piece. Offer a discount for bulk tickets sales.