I suggest going to your local thrift store, Volunteers of America, Goodwill, garage sale, etc., and see if you can find an old wool blanket. Here (in Michigan) I can usually pick one up for under $5. I simply wash and dry the blanket before using to make sure it will stay the same size. Since it's used, I'll wash it to begin with anyway! I used hot water/hot dryer with one blanket, which felted it, so it resulted in a heavy, stiff quilt with no draping quality which was what I intended-- because I use it for a 'door' for the stairway leading upstairs to keep the heat on the main floor in the winter. It's the last time I'll do that! It was murder to machine quilt-- it killed my walking foot. (A felted wool batting is really cool for a wall hanging too.) For a bed quilt I chose a very very thin wool blanket that showing good draping itself after washing with cold water/cool dryer. I simply continue to launder the quilt the same way and have had no problems with it.
I know some people like all new modern 'ingredients' for their quilts, which I like to do too, but I enjoy also creating with the old-school attitude for quilt making, that follows the American settler type tradition, where you use what patches, scraps, liner, etc. that you have.
Wool certainly seems to make a warmer quilt than cotton or polyester. Wool does have weight though. Sometimes on a cold night several quilts can feel like a ton over you... If only there was a way to make batting with feathers! A quilt top cover over a down comforter is just not the same as a true quilt. :-)