StartSSL has free certificates, or you can pay $60 for validation for a year which gives you unlimited certificates on unlimited domains with a 2Y expiry, so if

StartSSL has free certificates, or you can pay $60 for validation for a year which gives you unlimited certificates on unlimited domains with a 2Y expiry, so if your set of domains is reasonably static you only have to pay every two years. You can also get alt names on your certificates, so if you want to support IE on XP or Android 2.2 then you can put several domains on the same certificate. I have no interest in StartSSL, just a happy customer :).