Personally, I use an 80/20 cotton/poly blend. I know how batting has gone up.
Watch for 40% off coupons and purchase as much as you can afford, I have purchase a bolt of W/Natural at this time.
Hobby Lobby has them from time to time. Also watch on line ads and get special prices which include free shipping.
As a longarmer, I purchase by the bolt. I believe you can get the correct size for a lesser amount than a Queen size which you may not need one quite that large.
It is always hard for me to not put quality batting in when I have purchased fabric, taken the time to sew a beautiful quilt, I desire this piece to last.
Enjoy!