Update: This week there are more than 40 new Werewolf books added to the $6.95 sale. The previous books are still on sale.
Through the end of October there is a Audiobook sale at Audible.com. Last week there were a bit over 40 Vampire books for $6.95. This week 40+ Zombie books were added to the sale. Each week a new monster category are added (the previous monsters will remain). At $6.95 it is a pretty good deal if this is your genre.