In order to make HTTPS as default, GitHub based project is open to Public for the first time. It has already been tested with some group of volunteers. Its free and easy to use. There are some major players giving some freebies but this is very straight forward among all of them.
The issuing service is run by the California based Internet Security Research Group and is in public beta after running trial. It is trusted by major Internet Browser Applications such as Internet Explorer, Mozilla, Google Chrome etc.
You have to download an open-source client to your web server and can start using the Certificate. You just need to follow some simple steps.