Here’s a good overview piece by SP Ambassador Marc Towler on the subject:
https://www.marctowler.co.uk/using-lets-encrypt.html
and a link to our conversation, briefly, about the subject when it was in infancy:
If you aren’t reading above, Let’s Encrypt is a service that provides free SSL certificates to anyone. They have plugins for servers that work with Apache and Nginx, and you can basically run an auto installer package to make it much simpler for people to implement.
So, we have Let’s encrypt available, now. What does everyone think about it? How can we get people to use it? Will there be other providers who do the same thing? What does this mean for the future of paid certificates? Does this cheapen the value of certificates, in anyone’s minds?
Edit: Here, of course, is the link to the actual service: https://letsencrypt.org/