I back my rag quilts with good quality flannel: it softens beautifully and rags/frays great.....had a friend who used minky as a backing for a rag quilt and I seem to recall she was disappointed because it didn't fray but then figured it was a good trade off for a very silky soft backing. Cheap flannel won't fray or soften as nicely so it is worth paying for good quality flannel.