So, here's how the campaign shaped up.
Spending on Google Ads $100.67
Clicks 168 over 10 days
Cost per click $0.60
Total sales using the offered 40% discount on Smashwords -- zero.
Sales above the normal rate during the ten days $64.
On the surface you'd have to say it looks like, under the best case scenario, the ads don't pay off. But there are a few other observations I have. When I reduced my maximum $/click offer to $0.50, I still spent my full $10 budget per day, meaning for the first six and a half days, I overpaid (and received better placements, however). I also noted that no one used the discount I set up on Smashwords, meaning my landing page was not at all effective at converting interest into sales. And no question about it (at least in my mind), having multiple titles out there for readers to choose from will help also.
So, here's my thoughts. I'm going to let things settle down for two weeks, then run another campaign. This time, I'll have a specially designed page on my website for the landing page -- one specifically designed to easily move buyers into one of the normal purchasing channels. And I'll start the maximum $/click at 0.40, and see if I can still spend the $10 per day.
Once phase two of the experiment is over, I'll report the results here.