They are claiming there are 150 books for $5.95 but the listing only shows 139.
There are 92 for $8.95, for 231 total. You can sort/browse by price and/or category. Here's the link for the total list:
http://www.audible.com/guestauthor/Paperback_Sale_A3
Sale ends on 7/19/11 at 11:00 am EST.