There are a lot of recipes available to make Play Dough yourself at home. I am trying to provide a list of recipes I like.
YouTube Videos on Making Play Dough at home as they are very easy:
1. Play dough from scratch! - From: SteC0203
2. How to make play dough - From: lyly200
3. Make Playdough – From: cgtlv
4. Playdough St. Patrick's Day Green Cullen's Abc's - From: Cullensabcs
5. DIY Non-Toxic Toys: Packaging-Free Fun: by Alexandra Zissu
This recipe uses following ingredients. As per author if you store it in air tight container then it will last for 6 months or even more.
* 1 cup flour
* 1 cup water
* 1 tablespoon oil
* 1/4 cup salt
* 1 tablespoon cream of tartar
Read complete story at http://www.thedailygreen.com/living-green/blogs/organic-parenting/DIY-playdough-55090801