The local farbric store that is going out of business just posted they are up to 50% off on the quilting fabric now, so I plan on loading up on backing fabric. I've already bought two bolts of extra wide premium muslin, and may get another as I really like it.
I am going to be looking for fabric I can use as background and getting larger quantities. So much of my stash is 1-3 yard cuts and that is fine for piecing, but if I am doing a sampler quilt I rarely have enough for the background. So expanding that will be a big boost for me. And if at some point I decide I bought something that I just don't want to use on the front of a quilt, I can use it for the backing.