Recipe for paper glue
There are a few different ways of making your own glue, here are four different versions you can try :

Simple Glue Ingredients:
1/2 cup flour
1/3 cup water

Paper Mache Glue Ingredients:
1 cup flour
1/3 cup sugar
1-1/2 cup water with 1 tsp white vinegar mixed in

Cornstarch Paste Ingredients:
1-1/2 cups cold water
2 tablespoons cornstarch
2 tablespoons corn syrup
1 teaspoon white vinegar

Simple No-Cook Flour Paste:
1 cup flour
1/2 cup water
1/8 teaspoon salt

Taken from http://www.wikihow.com/Make-Glue