The price on this has just been reduced by a very large amount and i believe this is the cheapest price available anywhere.
Product Desscription: Secure all your subdomains on multiple domains all under one single SSL Certificate to save on management and costs. You will be able to secure 2 wildcards in the standard order while being able to add/edit and remove additional wildcards at anytime, as needed. You can secure different TLDs if required and also install the Multi-Domain SSL on an unlimited number of servers.
StartCom will give you an unlimited number of multi-domains and/or wildcards certificates for US$119.80 (~AU$158).