I buy backing fabric that is the same as one of the fabrics in the top. That means that my backing has to be pieced; but that is fine with me. I do try to get enough fabric so that deiigns match where seamed and it is difficult to find the seam. Since I am not the greatest FMQ, I select printed fabrics that will not highlight my quilting. For solid fabric backing, I send my quilts to the LAQ.