Prices highly depend on place where the hardware is sold. Here (in Poland) you can get easily an used MorphOS compatible PowerBook for around 600 PLN (190 USD). Prices dropped much after Mac OS X 10.7 release - Example. I got myself a powerbook5,6 for 175 PLN (55 USD), with a broken matrix and overally far away from a perfect visual shape. Used 1280x854 matrix costs 100 PLN (30 USD).

[ Edited by Korni 11.11.2011 - 17:56 ]