Facebook ad - final numbers

Campaign reach: 160958  (number of people who saw the ad)
Frequency: 1.5 (average number of times ad was seen per person)
Social Reach: 629 (people who saw it)
Actions: 101  (actions taken within 24 hrs of seeing the ad)
Clicks: 137
CTR 0.062%  (number of clicks divided by the number of times it was shown on FB)
Spent $50 (out of $50)
Price $0.23  (Average cost per click for 1000 impressions)

Pages likes -  19

Cost per like - $2.63

To me, this doesn't seem worth it - $50 for 19 likes. Just to put a figure on it, 0.11% (yes .00011)  of the total reach "liked" my facebook page. There are a couple things I have to question about this.

if I had spent thousands on this ad, rather than $50, would the outcome back been better? From the way I understand it, the amount you spend dictates how often it shows up over the course of the day(s) it runs. So, the more you spent, the more often it's shown. I don't know how they decide when to show ads. So, for all I know my ad was shown at 6am every morning for 20 minutes and that's it.

Out of that 19 likes, how many of them will buy my book? So far, I've sold exactly 1 in the 3 days its been out. For all the additional advertising, social interactions and book reviews I've had - that's all it's added up to. 1 sold. So, let's say one of those 19 people bought it. That 5% of the total. That is not horrible....if that were the case. Somehow I doubt that is the case.

So, there's the total numbers. Take it or leave it, it's up to you. I thought I'd provide some stats because no one else ever seems to, they just want to TELL you it was good or bad. Forget that, I'd rather bring numbers and either prove it to you, or let you make your own assessment.