A wildcard certificate is a type of SSL certificate which can be used with multiple subdomains. Most commonly subdomain count is unlimited and that makes Wildcard SSL Certificates cost effective when you need to secure more than a few subdomains.
There are several Wildcard SSL Certificate brands and variations to choose from. Most popular ones are:
- Comodo PositiveSSL Wildcard Certificate
- Comodo Premium Wildcard SSL Certificate (business validated)
- GeoTrust TrueBusinessID Wildcard (business validated)
- RapidSSL WildcardSSL Certificate
Wildcard certificates are getting more popular because it's very common for a website to use additional subdomains. Subdomains can be used for webmail, authentication page, API, administration panel, support page and similar. Some examples of subdomain usage: login.yahoo.com, support.getssl.me, search.about.com (the underlined parts are subdomains).
As you can see there are countless ways to use subdomains and you already know that each one of them must be secure. GetSSL.me is the cheapest place to buy Wildcard SSL Certificate: Comodo PositiveSSL Wildcard is starting at just $99.95.