cvbbs.com is having some crazy good sales on a couple good books:
Total Truth for 6.99 (hardcover!) - although I didn't fall in love with this book, it's certainly worth having at this price.
Counted Righteous in Christ for 3.99 - an important defense of the doctrine of imputation by John Piper. It is a little technical, but still worth having.
My Soul Magnifies the Lord for 2.99 - Martin Lloyd-Jones' sermons on Mary's Magnificat. His sermons are always worth having, regardless of the price.