To help promote their new eBooks, through March 31 Pearson is having a sale on CCNA prep materials at http://www.ciscopress.com/promotions/promotion.asp?promo=138638. It includes a sweepstakes to win the CCNA 640-802 Official Cert Library, Simulator Edition, CCNA Video Mentor, and one (1) CCNA Exam Voucher. Estimated prize value (US): $525.
For other certifications they are also having a Buy 2 save 35% sale. See http://www.pearsonitcertification.com/promotions/promotion.aspx?promo=137551 for details.
As always I suggest you comparison shop for books, I recommend http://www.bestwebbuys.com/books/ for comparison shopping for books.