The first thing I did was look up where Paradise was incase you were close to Anaheim and didn't know about M & L Fabric Discount store, but you are too far away to go there on a whim. I piece my backs because I can find quality fabric (Kaufmann) in the flat fold section for $2.49. I also check out what Connecting Threads has in their discounted fabrics also, and lastly what folks are seeing here on the QB reasonably. For any bed size quilt I always buy 10 yards, this gives me enough for the backing, binding and a couple of pillowcases usually. Any left overs go in the scrap heap for scrappy quilts. I have bought 108 inch wide fabric also but not as a rule. Back art is popular at our Guild and members use a multiple of fabrics for backings and the effect can be really nice. Good luck!