I purchased bolts of cotton sateen in black and cream. One side is shiny, and the other side is regular, kind of like glossy and matte paint. I use both sides to give movement to the quilt. It is the most expensive fabric on my shelves and came in a 10 yard bolt. My LQS special ordered it for me, so I paid full price. But it is worth every penny. I used the cream for background fabric on some needle-turned applique blocks, and the sheen of the fabric really made the blocks.
I also buy bolts of Kona cotton (especially black and snow), muslin, fusible interfacing, regular interfacing, and teflon fabric when it is on sale or if I have a 50% coupon. I would buy batting and Insulbright by the bolt if I had a place to store it (if I ever get a LA machine, I will definitely buy it by the bolt).