I actually started a reward scheme with the kids, a sticker for good behavior/ for getting perfect score in their spelling or homework. Each point has a value of a dollar. When they collected enough, they can cash it in to buy whatever they like. It's that cool? The kids love it, it makes them work harder and go extra mile for greater achievement.
Afterall, we're ourselves were not born with a silver spoon in a mouth, we worked hard to get to where we are today, and it sure helps knowing that that's also the value that we're teaching our kids, gold coins don't just drop down from the sky, you got to earn it.