So, I released a novel on Amazon, Feb 7th, it went free for 3 days on Feb 8-10, and then back to the full $2.99 price.
It's my third book on Kindle, I have another novel and a short story collection, and my first venture into KDP select.
Short version, I'll probably take that route again.
To give a baseline, I had 5 total sales in January, 3 of the existing novel, and 2 of the collection, which I released simultaneously on Amazon and Smashwords for $0.99.
With the new novel, I had 7 sales in the 12 hours before it went free (which I had previously announced), and another 76 in the remainder of the month. I also had 5 sales of the other, unrelated, novel on Amazon and 1 on Smashwords.
The collection didn't move at all in February.
I break it down in a few other ways on my blog,
here.