I haven't found anywhere that does music books cheap. [img]smileys/smiley19.gif[/img]Most local music (instrument) shops will order the books in for you if you ask them. However this site might be worth a look, it was advertised on the back of one of my books:
http://www.musicroom.com/se/ID_No/057904/details.html
[img]smileys/smiley2.gif[/img]