If you were to write an AdWords ebook, I would buy it. Like a good one, I could easily rationalize spending lots of money on it.
Instead, I prefer using what I know to make money directly (not necessarily limited to increasing my share of the teaching bingo market, hopefully) and possibly doing some consulting. Folks working on their next bowl of ramen can read my blog for free. I get emails saying mostly positive things. Everybody is happy.