I carry Hobbs 100% Wool batting, 100% poly, 80/20 cotton/poly or cotton/wool blend batting in 96" and 120" rolls. Cost for both is 20 cents a linear inch or (sorry for the math) .003 x square inches. I recommend the wool for large quilts since it is lighter in weight and nice and warm. I often have Warm & Natural 100% cotton in various sizes too.
I usually stock various large backings, around 108" x 108". Cost is usually about $45. Below are photos of current stock. I also have a white on white floral, which didn't photograph well.
Why buy batting from me? Unless you have one of those famous coupons, I can beat the retailers' prices in almost every case. I carry top quality Hobbs batting in large rolls so I do all the lugging and you don't have to. But the best reason is that, in these big rolls, the batting is smooth and uniform. The packaged batting doesn't always lay flat which can cause lumps in your quilt no matter how carefully I keep an eye on it.
Consider one of the batting types I carry for your next quilt.