I've seen a few posts about people getting pretty good results from a Kindle Ad Campaign. I unfortunately didn't have good results. Here's what I did for others to learn from.
I ran my campaign from 11/27/15 to 12/24/15 for my book Meowy Christmas.
The minimum amount for a budget is $100. So I stuck with that.
I read several articles and almost all suggested targeting specific products for your ad. So I targeted every Christmas book I could find.
I started with the default cost per click, which was I believe was 33 cents. I left that rate for a week and a half and raised it to 40 cents. After another week and a half, I raised it for a final amount of 45 cents.
The stats were as follows:
Click Through Rate: .076%
Detail Page Views: 249
Average Cost Per Click: $.33
Estimated Orders: $0
Estimated Sales: $0
I am not sure who saw my ad. I had several people search for it under the products I targeted and no one saw it, myself included.
While I didn't sell any books via the ad, I did sell 11 paperback versions and 23 kindle copies during that time. Not great but better than nothing.
Would I do it again? Probably not. If they lowered the minimum to $20, I may think about it.
I hope this helps anyone thinking of running an Amazon ad. Feel free to ask any questions and I'll do my best to answer them.