Diane Duane's Young Wizard (New Millennium Edition) series is now available as a nine volume set from
http://ebooksdirect.dianeduane.com/ for $55 or so.
Use discount code CANTWAIT with the next few hours for 60% off. Use discount code BOX50 for 50% off if you're too late for the CANTWAIT code.
CANTWAIT expires at 23.59 on 23rd October, Hawaiian Time.
BOX50 expires at 23.59 on 31st October, Hawaiian Time.
With CANTWAIT it's just $22 for the nine volumes.