There are lots of great reading incentive program for kids! All of them are completely free and some of them are available all year long. Summer Reading Local Public Library Your local library is very likely to have a program for summer reading.
* Here is a great way to encourage and reward readers. Over the summer I actually participated in an adult book bingo sponsored by my local city library. It was a lot of fun and really did push me to try some books that I wouldn't have otherwise.