Let's EncryptTry Let's Encrypt
Let's Encrypt Overview
A new certificate authority that's free, automated, and open. Let's Encrypt aims to allow anyone who owns a domain (including this site) to use a trusted certificate to secure their server at zero cost unlike other CAs that may charge over $100 per year to do the same. It also includes a command line tool that runs on your web server that makes it painless to obtain a certificate, securely configure it for use, and automatically take care of renewal. Let's Encrypt is backed by some big sponsors, including Cisco, Mozilla and Facebook, and has just entered public beta so can now be used by everyone.