I didn't buy any ebook when I started last year october. You can learn most things by doing and reading DP. The trick is not to loose any money over time. Start with a small budget. Monitor your campaign closely. Some super affiliate say they loose $10,000 for a new campaign. But that is when they have earned large cumulative profit money.
Keep in mind that you want quality and not traffic clicks. Quality means high targeted keywords, which convert into sales at a very high rate. Don't spend a lot of money on PPC at the beginning because even 10-20$ a day can turn into 400-500$ if the keywords are highly targeted.
Don't waste your money on e-books. Here're all you need: http://www.google.com/adwords/learningcenter/ http://adwords.google.com/support/
Experience is the best teacher. Reading their faq is wonderful, but it's not coming from a marketers perspective. There is a lot missing from those faqs, (by design so you spend more money testing.) Be careful with anything you buy because the majority are just fluff.
I started with the Google Learning Centre, provides you with a sound base. Perry Marshall is a good place to start when you have a grasp of the basics, great tips on developing and improving your skills
Most of what i know has come from Adwords Killer. There are a few other quality books out there that teach u the ways.