It's a clever promotion for Pride and Prejudice and Zombies: The Classic Regency Romance - Now with Ultraviolent Zombie Mayhem! Copies are only $7 at Amazon and of course would make a perfect holiday gift.
Even better, the kits themselves are also available for purchase. Lizzy Bennet has her own Etsy shop where you can purchase your own Unmentionable Preparedness Kit:
A kit of balms, salves, and restoratives from my apothecary, which you may use to defend yourself against the impending zombie plague. Additionally, a hardcover biography, Pride and Prejudice and Zombies, a tale inspired by my family’s struggle to defeat the unmentionables.The other major characters also have their own web presences, including OK Cupid profiles, Facebook accounts, Last.fm channels, and more.
Includes Bleed-Banishing Balm, Gnaw-be-Gone Purifying Poultice, Reanimate and Perambulate Smelling Salt.