I will use acrapes of material for my backing eaither from the project I am working on or material from my stach that will work. I also will use sheets, they make great backings and are cheaper in many cases for backing. I know the wuilt stores will always not to do this, but do not forget they are in the business of selling material. As a long armer I will tell my customers that if they do have a peiced backing I cannot always guarntee that it will be perfectly sq. I love have a story on the back of my quilts as well as on the front.