Are you looking for an effective whole class reward system? Use this Brownie Points system to reward whole class behaviour. Once the class fills up the whole brownie tray, you can have a class prize (e.g. a movie, game, class party etc).
There are displays for brainstorming specific behaviours that can lead to a brownie point, as well as target displays, for when you want to specifically target a behaviour.
Brownie points are available in 2 sizes and a variety of brownie trays are also included. You could also use a real baking tray!