I'm a member of a BOM at a local LQS($9-$11pr yd stuff) and they only give you enough fabric to cut your blocks with very little left over (maybe a quarter inch now and then). Since the fabric isn't prewashed I had some shrink HORRIBLY and it was 100% cotton, the buyer had just purchased some cheap fabric to pass off as good stuff. I had to substitute fabric from my stash. SOoooo, what I'm trying to say is that if it wasn't prewashed even cottons can shrink up a lot if it's cheaply made fabric.