The Art of Discount Travel (now revised and updated) is chock full of strategies and resources for lowering the cost of flights and accommodations. From significantly discounted to free – yes, free – multiple cost-reduction strategies are presented in detail. This book was written with you, the consumer, in mind. If a cost-cutting strategy is legal, ethical, and available to the general public, you will probably find it in The Art of Discount Travel: Your Guide to Cheaper Flights & Cheaper Nights.
Although the author takes his travel hacks seriously, the book is sprinkled with anecdotes that are both instructional and amusing. $0.99 on Kindle.