Months ago, we had started using a reward chart for our 4yr old to help him focus on things he should be doing. He would earn stickers for doing each thing listed on the chart daily. I had recently set up a store in the corner of my bedroom filled with small toys and books. Each item is tagged with how many stickers it costs.
Currently, Jake can earn up to 7 stickers per day. One each for finishing all his food, carrying all his dishes to the kitchen sink, cleaning up all the toys by the end of the day, practicing writing, reading and answering one question correctly about each of 3 books, and two stickers for being "nice" to his 1yr old brother and sister. This means not knocking them down, grabbing them against their will, etc . . .
One of the items Jake had his eye on in our little store was a small Mega Bloks Dump Truck kit. The price of this dump truck kit was 50 stickers. He started today off with 43. For the first time ever, Jake managed to earn every sticker possible in one day. I had doubts that it could be done based on previous months, but today he proved that it can be done.