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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.
Which of them is free?
Free has zero value in the enterprise world if managing certificates is a nightmare. Certificate prices is insignificant when your average website is a 90.000€ project.
Exactly, enterprise world. Letsencrypt doesn't aim for that.