Certificates
Issued and renewed automatically on every service. The paid ones exist for the cases where an auditor has asked.
Domain validated
Issued automatically on every service, renewed automatically, included. This is the right answer for almost everything.
Organisation validated
Available where a client needs their company name on the certificate; most sites do not.
Wildcard
A wildcard is included on every plan and covers every subdomain you create.
Tell us what you are running now and we will tell you plainly whether moving it is worth your time.