Agreed @wcs Window Cleaning Marketing by @Chris is a must have for anyone starting out in the business. The methods are proven, it cuts down on startup time, and helps you hit the ground running.
$25 is more than reasonable for such a valuable resource.
Beyond this book, I would recommend the following:
Think and Grow Rich - Napoleon Hill (a classic that I read once a year)
The E-Myth Revisited - Michael Gerber (an entrepreneurial bible)
Profit First - Mike Michalowicz (It will change the way you look at profitability)
As a Man Thinketh - James Allen (it’s all about the power of the mind)
Blink - Malcolm Gladwell (understanding decision making and how we go about it)
My Life in Advertising and Scientific Advertising - Claude C. Hopkins (This is what Mad Men was all about. Not light reading but it will change your approach to marketing - a classic)
7 Habits of Highly Effective People - Stephen R. Covey (it will shift how you prioritize things)
Unlimited Power - Tony Robbins (another book on harnessing the power of the mind)
