I watch for sales especially those that have the remainder of the bolt for at least 50% off, then I look for ones that could be used for a backing if there is enough yardage on the remaining bolt. Now, I don't always have a completed top for the backings, but I have chosen's one that are neutral or something in the texture and colors I usually work with and haven't bought a specific backing for a finished top for years; shopping instead from my backing stash. Right now, I have about 10 potential backings with at least 8 yards of fabric. I don't make show quilts but make ones that people will actually use, can be washed and dried in the machines. I do buy good quality fabric though, just on sale. I did years ago buy some on sale that had bold patterns and interesting, each of these found a quilt top that actually worked very well those backings! Batting I buy by the roll and that has gotten really expensive now especially as I have to have them shipped. I am also working on using up my batting stash although I only have 2 partial rolls and a few packaged.