SSL is a security protocol used on the web which keeps data transferred between a website and a website visitor secure against being spied upon. There are a lot of technicalities involved that make this happen, but Google announced back in August of 2014 that SSL sites would stand better in Google rankings than sites not using SSL.
we're starting to use HTTPS as a ranking signal. For now it's only a very lightweight signal — affecting fewer than 1% of global queries, and carrying less weight than other signals such as high-quality content — while we give webmasters time to switch to HTTPS. But over time, we may decide to strengthen it, because we’d like to encourage all website owners to switch from HTTP to HTTPS to keep everyone safe on the web.
SSl certificate prices vary, but for basic SSL you can expect to pay between $2 (NameCheap.com) to $50 (HostGator.com) per year for a basic SSL cert with installation. Contact your hosting provider, or contact me for assistance. 505-274-1132.