Incentives

For the past 5 years I have given the kids "tickets" for good behavior, returning papers, etc. They love this. I don't. I like rewarding them for good things, but what to do with all those tickets? I have a treasure box, but keeping it stocked with things they like is expensive and cumbersome. Plus on days where they can "shop" takes forever! Valuable time that we don't always have. I need some ideas for what they can "purchase"with their tickets. Think, Think, Think...