We provide free SSL certificates through the Let's Encrypt initiative. These SSL certificates are an effort by Google to help encrypt all websites in the world. While they do provide a basic level of encryption it does have to be frequently renewed every 90 days. 

If you run an eCommerce site you might want to consider a higher level of encryption such as 256bit EVSSL certificates. These high level certificates require more verification but give users a higher level of trust and they can be renewed a year at a time. Sites with EVSSL certificates report a 25% increase in sales conversions vs standard level SSL certificates.