StartSSL also provide free certificate : https://www.startssl.com/ https://www.startssl.com/ You might also want to use http://www.cacert.org/ http://www.cacer

StartSSL also provide free certificate : https://www.startssl.com/ https://www.startssl.com/ You might also want to use http://www.cacert.org/ http://www.cacert.org/ and don't forget https://letsencrypt.org/ https://letsencrypt.org/ If you have budget and want to use for multiple sub domains you might want to buy wildcard certificate which can be used to secure *.domain.com. Domain validated certificate is good for security. having a organization validated or extended validation certificate will not improve your security.