I go to Paducah quilt show every year and one vendor has thousands of pre cut 18 x 18 batting squares for sale cheap. From cotton to wool to silk. I buy bags of them. It's so much easier to cut from a precut piece when I need lots of small pieces. Here is a website that has pre cut Warm and Natural of different sizes. Interesting it's an embroidery shop.
http://www.spaghetti-legs.com/servle...re-sets/Detail
There is now a batting scissor for sale that is much better then a rotary cutter. It's great.