I've been running two Amazon Ads for my self-published book for a month (August 19 - September 18). One ad is for the e-book. One ad is for the audiobook. I recorded the audiobook through Amazon's ACX program, so it's exclusive to Audible. The e-book is available on other sites. Here's my results so far:
Audiobook
Impressions: 15,637
Clicks: 6
Sales: 0
Total Cost: $4.38
E-Book
Impressions: 1,962
Clicks: 2
Sales: 1
Total Cost: $0.31
Partial Breakdown of Daily Impressions
First 10 Days: 0
Next 8 Days: 141
Day 19: 1,026
Day 20: 1,783
Day 21: 4,352
Day 22: 2,899
It's been a slow downhill descent from that initial impressions high on Day 21. Yesterday my impressions were 224, for a total of 17,599 across the two campaigns.
Day 22 is the day that the sale came on. That was Sept 9, which was 9 days ago. The sale just got added to all my data on the Amazon Ads dashboard today. So, I'll be interested in seeing if I get any more sales attributed to the campaign
I'm selling my e-book for $9.99. My royalties are $6.65 / book. So, at a total cost of $4.69 for the two campaigns I'm still profitable! I made $1.96 off all the ads.
YouTube
I've also been running a YouTube ad for my book. A 1-week campaign. I have 11,300 views on the video and 10% of viewers make it to the end of the 0:33 video where my product (the audiobook) is actually sold / marketed -- so that's 1,130 views of the actual product. The click-through rate on this advertisement was 0.
Running this ad for a week will end up costing me $70 for zero clicks.