Strategy: An Intro to Game Theory; 2nd Ed; Joel Watson in La Jolla, CA
This is the book used in UCSD's Econ 109 course. The author is Joel Watson and it is the edition that is currently used for the course. The book was bought new and was used for one quarter. The book store asks for $83.10 and I am asking for only $65. That is ~$20 dollars cheaper!