Browser security authorities are requiring HTTPS connections per their security settings and marking the non-SSL sites as insecure, which in essence is true. Also search engines are rewarding SSL enabled web sites on their search rankings for some time now.
What SSL does is it secures the connection between two peers so that no one in the middle can read the content of the traffic. This in turn prevents the leak of sensitive data like passwords and other private credentials. We suggest you use non-free SSL certificates on detail websites since they provide extended feature sets that make your customers more comfortable visiting your website. Also free SSL certificate systems offer no support. If you will opt for a free SSL, there is Let’s Encrypt, a non-profit organization that is supported by many global companies and volunteers.
Paid certificates are issued for 1 or 2 years, which after that you will need to renew whereas free certificate providers support 90-day certificates. After they expire you can easily apply for a new one or simply use their tool to automatically renew the issued certificate on your server.