Purpose is not just for big corporations. Nick talks about harnessing the power of purpose at his two pizza restaurants in his Ted talk below.
He has a great explanation on the difference of "Purpose" and "Mission and Vision" (around the 2:40 mark):
Purpose is different from mission and vision. There are some great mission and vision out there, but they're future oriented. We're striving to get something, somewhere, someday... Purpose is present tense - here and now. It's why we do what we do. And it's specific.
He goes on to explain what values are:
Our values are how we do what we do.