Looks like FT Press may be cycling through and giving a few away. I'm not sure how often these change, but the current free selection is:
Disrupt: Think the Unthinkable to Spark Transformation in Your Business by Luke Williams (Dec 8, 2010)
FranklinCovey Style Guide: For Business and Technical Communication (5th Edition) by Stephen R. Covey (Jun 7, 2012)
Extreme Money: Masters of the Universe and the Cult of Risk by Satyajit Das (Aug 4, 2011)
Marketing Strategy from the Masters (Collection) by PHILIP KOTLER, Paul W. Farris, Neil T. Bendle and Phillip E. Pfeifer (Oct 19, 2010)
The Truth About Perfecting Your Presentation Skills (Collection) by Michael Solomon, James O'Rourke, Natalie Canavor and Claire Meirowitz (Nov 3, 2010)
Making Sense of People: Decoding the Mysteries of Personality (FT Press Science) by Samuel Barondes (Jun 21, 2011)