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Let's Encrypt Announces New-Certificate-Every-6-Days Offering
(letsencrypt.org)
This is a most excellent place for technology news and articles.
You can make your own cert. To make sure your cert belongs to you (your site) it is signed by authority and the client then may verify that authority (which cetificate is preinstalled in their system) in fact had verified ownership of your site and then signed your cert claims with their private key.