Since the beginning, I enrolled White Dwarf One in KDP Select. Basically you give your ebook in exclusive to Amazon, and you get a couple promotional advantages, namely the possibility to set your book as free for 5 days in each 90-day enrollment period.
I set White Dwarf One free during last weekend – forgetting that it was a 4th of July weekend – and scheduled a few tweets and Facebook posts with Buffer. I also advertised the promotion on 4 websites that list free Kindle ebooks (I had a list of twenty-something, but many require a certain number of positive reviews, which I don’t have, or simply ask money, which I don’t want to spend right now).
In total, readers downloaded 139 copies of the ebook: 96 on Saturday, and 43 on Sunday.
Accidentally, WDO reached #6 in Top Free sci-fi First Contact books, and #9 in Top Free sci-fi Space Exploration, as these two fantastic screenshots will document to eternity.
Given the amount of marketing was close to zero, I think it’s a satisfactory result. After all, potentially, more than a hundred people are reading my book now.