I bought my copy from Amazon. Costco and its’ former boss can go suck an egg.
So did I.
I bought the Kindle ebook version. At the same time, I bought the Audible audio book version. When you buy a Kindle version you can buy the Audible version for only a couple of dollars more. It is great for listening when you drive.
If you buy a conservative book at a brick & mortar store it will somehow never make it onto the New York Slimes best sellers list. If you buy it at Amazon it will be included in the Amazon best sellers list.