Illegal copies are also a rampant problem on Amazon, though, so this increases the odds that the big Buy Button ships you a counterfeit.
https://twitter.com/billpollock/status/844030960333152256
https://www.ft.com/content/5dba91b0-e1c7-11e6-8405-9e5580d6e...
https://www.inc.com/sonya-mann/amazon-counterfeits-no-starch...