There was a point in the early days of indie publishing when the FREE! book promo was one of the go-to gimmicks. Tales spread among the author blogs about huge sales tails that would follow a 3-4 day run on the Kindle free lists. These surges would more than pay for the advertising required to spread the word back in the glory days of free in 2010-11.
I released my first novel, The Greatest Show on Dirt, in February 2012. I ran a free promo on Amazon, gave away 5,124 copies in April of that year, and saw a modest sales bump when it returned to regular price. Maybe I missed the window on free, maybe my book wasn't quite the right genre to ride the wave. I wasn't sold on free, but I wasn't ready to completely write it off, either.
In July 2015, I dabbled with free again with my second novel, Nine Bucks a Pound, also a baseball-themed story. According to my records, which I have no reason to doubt, I didn't spend anything on advertising this time. I moved 1,147 units. I sold a handful at regular price afterward. Again I was left wondering whether there was more potential for this. Certainly advertising would have helped generate interest, but would it have meant more paid sales after? And how many free downloads would be required to result in a bona fide sales spike? I could only guess.
The last time I bothered with a free promo was March 2018, when I ran one for my third novel, Sorry I Wasn't What You Needed. This time I spent $78 on a total of three ads, and I saw 3,668 free downloads as a result. Sales spike? Not quite. Depends on your definition of spike. I was disappointed enough that I figured I wouldn't bother with free again.
Yet here I am, giving it one more try. This time I'm giving away The First World Problems of Jason Van Otterloo, my fourth novel, from Thursday (9/5) through Sunday (9/8). And I'll be honest, free is something of a desperate measure here. This book just hasn't seemed to catch on. It's received some decent reviews (and a couple of lame ones), but not enough overall.