I use everthing people mentioned plus newsprint end rolls that you can buy at your local newspaper office. End rolls are the part of a roll that is too short to go through the printer. Some newspapers give end rolls away. Others charge two or three dollars for the paper, which is neatly rolled on a center core. The paper will probably turn yellow with age before you use it up.
Teachers love end rolls for projects with students because it is inexpensive and they get to recycle it twice, once when their students use it and once when it goes into the recycle bin. froggyintexas