You are wrong. At StartSSL, you can get an unlimited number once they validated your person, which costs 60$. That validation lasts for a year. During that year you can generate as many wildcard certificates as you want.

See https://www.startssl.com/?app=25#27

"The fees for Class 2 (60$) and higher are applied to the verification and not for the certificate(s), i.e. you pay for the validations we perform. Once validated there is no limit placed on the amount of certificates one can receive (This depends on other limitations such as uniqueness of the subject line for example)."

Edit: They cover exactly their costs. The cost is at validating your persona (they call you, you fax them scans of your passport/drivers license/etc, they need to check that etc.). Issuing a certificate is fully automatic so there are no costs associated with that, so they don't charge for that.

But why do wildcard certificates need more validation in the first place?

Thanks! That's good to know! (But irrelevant to the discussion anyways.) Edited the info in the parent comment for further readers.