All the ingredients are common ones which you can get in the baking section of  your local grocery store; just ask for help if you can't find them.

Mix the following 5 ingredients in a heavy pan over low heat:

3 Tablespoons cooking oil
2 Cups water
1 Cup table salt
4 Teaspoons Cream of Tartar
Food Coloring in your choice of food color

Then add slowly, and stir between adding, to avoid lumps.  Small lumps will blend in at the last stage when you knead. 

2 cups white all-purpose flour

Cook and stir constantly over MEDIUM heat till it thickens to playdough consistency.  Remove from heat and let sit until cool enough to handle.  Place dough on counter or cutting board and knead until smooth. 

Store in plastic bag in refrigerator.  Will keep for months.