I have found websites that sell vibration motors that are half as powerful, but only cost $2.00 USD. These motors are lower quality (not as powerful, and precision microdrives must have some reason for selling their motors for so much).
http://www.pagermotors.com/Products.php?f_category=Pager
I also have found websites with hat version of this haptic compass with construction info and code for Arduino.
http://www.stanford.edu/~tanders/VibroHat%20Home.html