Why does it cost $20 a month for Custom-domain SSL on Heroku? [closed]

Question

Please note this is not a complaint. I am just wondering what the cost is to Heroku for providing custom-domain SSL, if there is one, as they do not provide the SSL certificate. As i understand it it is quite common to provide SSL support for free, and charge for the certificate itself.

For reference: Custom-domain SSL

Answer 1

In order to use your own SSL certificate with a shared server, your site must run on its own dedicated public IP address.
(since the server needs to send the SSL cert before the browser tells it which host it's connecting for)

IP addresses are a scarce commodity.