I would say it depends on how and where you are trying to raffle the centerpiece. I have a friend that makes soaps, candles and gift baskets. At work around CHristmas time she would make up a basket and sell squares for it. She would figure out how much she needed to get for the item and would make up a sheet of paper with that many squares on it. It would normally be between 20-40 squares. Then we would pay $1 per chance and write our name in a square. When the squares were full she would cut them up put them in a hat and draw the winner.