Wheatpaste is a very simple glue that will cost you under a buck a gallon to make. It's just flour and water. The main advantage of wheatpaste is not only its cost, but if you need large quantities of glue, you probably already have everything you need in your kitchen. No need to run to the store and buy anything.
Step 1: Background (skip to Recipe Below)
There are lots of different ratios for flour to water posted online, but people who make it in large batches, and actually know what they're doing for recommend a ratio of flour to water 1:4.
(As in one cup flour and 4 cups water.) This ratio is suitable for glue, and when dry it will appear fairly clear, so it is the ratio I will use.
Wheatpaste is known to be just as strong as diluted white glue (stronger than straight glue) when used on paper or pours materials.
White flour is recommended over whole wheat flour, although whole wheat can be used. Whole wheat contains all parts of the wheat: fiber, protein, and endosperm. White flour has been processed to contain only the endosperm which is almost entirely starch.