It might actually be less expensive to buy some "cheap" fabric and cut squares. They will be bigger and you will have many for the same money. Don't worry about hemming the edges, just save them for emergency use and they will be fine.
Do not know where Debbie lives but you can buy bandanas for about $1-2 at Recreation Outlet in American Fork. Good cotton material will cost at least $6 a yard and to get 4 bandannas you would need to buy about 1 1/3 yards. I would just buy them unless you have a lot of material laying around and time on your hands. My wife who sews a lot does not recommend not hemming.
Oh, I know, hemming is better but not everyone sews. This is stuff that would be put away for emergency use. I've got some "cheap" fabric ($1-2-3 a yd). Good cotton isn't required, as nice as it would be to have. But we are talking emergency supplies. I can make 2 36" squares from cheap fabric for less than the bandanas. It may only work for one or two uses, but normally emergency supplies are gone with just one use.