We have a discount store near where I live called Roses. They sell blanket "seconds" for 6-7 dollars. I have been using them. They make a great warm quilt. I tie them. But I don't have to worry about them coming apart like some batting will. Whenever I find them in king, queen or full size I will purchase 5 or 6 at a time.
I just had to pay 35 dollars for a king batting, I needed it quick and could not wait for it to go on sale. So 6-7 dollars is a steal.
I also have used sheets for backing.