For instance, a second hand copy of a paper book is generally much cheaper than a new one, doesn't travel widely, and gets less valuable as its wears out. (activitypress.com)
If you can get your hands on a second hand copy, I thoroughly recommend it also. (wexboy.wordpress.com)
It can be helpful to keep on hand copies of both the teacher letter and the instructions for the student letter to give new students as they enter the class later in the year. (edutopia.org)