A good majority of my stash is from thrift stores, garage and estate sales, the clearance section of various places, and the remnant bins. A few weeks ago I got two 7/8yd pieces of tonal extra wide backing from Hobby Lobby and I paid less than $10 for both. That's a lot of fabric. For table runners and large quilts I usually use wide muslin for the backing, no one seems to care what the back of the quilt looks like and I'd rather spend my money on the front fabric. It surprises me how often I find large pieces of yardage or partial to full bolts of wide muslin at thrift stores. Plus I don't like piecing backs.
Cari