I listed 38 audiobooks today, most unabridged, and have the following unpostables to offer, one free with each audio ordered (or 2 regular books if you don't want any of the audios but do want print books).  If you want more than one unpostable pm me and we'll see what we can work out.

These are "unpostable" because they are all "personal copies", meaning they are not the originals but copies I made for my personal use so therefore not postable.  There is nothing wrong with them as far as quality.  To the best of my knowledge, all played fine last time I played them. 
 
Diane Duane:
High Wizardry: Young Wizards Series Book 3 - 7 CDs
A Wizard Abroad: Young Wizards Series Book 4 - 9 CDs
A Wizard Alone: Young Wizards Series Book 6 - 7 cassettes
 
Louis Sacher:
Wayside School is Falling Down - 2 Cassettes
Sideways Stories from Wayside School - 2 Cassettes
 
Tamora Pierce: Circle of Magic Series
Briar's Book: Book 4 - 4 cassettes
 
Tamora Pierce: Protector of the Small Series
Page: Book 2 - 5 CDs
 
Holly Black: The Spyderwick Chronicles:
The Wrath of Mulgarath - Book 5 - 1 Cassette
 
J.K. Rowling:
Harry Potter and the Sorcerer's Stone: Book 1 - 6 Cassettes
Harry Potter and the Chamber of Secrets: Book 2 - 6 Cassettes
Harry Potter and the Prisoner of Azkaban: Book 3 - 7 Cassettes
 
Ann Brashares: Sisterhood of the Traveling Pants Series:
The Sisterhood of the Traveling Pants: Book 1 - 4 Cassettes
The Second Summer of the Sisterhood: Book 2 - 8 Cassettes
 
Christopher Paolini: The Inheritance Cycle:
Eragon: Book 1 - 10 Cassettes