I also get mine at Uline.com I buy the rolls of 18" wide newsprint and do two layers of newspaper per tub. I also have a paper cutter that I bought from them years ago which you need to get if you want to buy it by the roll which is easier for me since I have so many different sized tubs. A roll lasts a long time, the shipping is cheap too. They have a hub in Eagan MN so they don't have to go too far for me.

http://www.uline.com/Browse_Listing_1954.asp?desc=Rolls

Mark