The last "yard" sale I attended was put on by my guild. I got every kind and brand of rotary rulers for 50c each. Patterns, the expensive ones for quilts, at 5 for a dollar. Most never used. Fat quarters and fabric for practically nothing. I came home with two big shopping bags full after spending only about $15.00.
The sale was for the guild's coffers, so no one felt the need to charge a whole lot for their stuff. They mostly just wanted to get rid of it, and get it into the hands of fellow quilters. 8-)