Comment Since you need FCRDNS to send mail these days (Score 5, Informative) 299
That means you have to control at least one IP address.
It's also really hard to send e-mail without at least one domain of your own.
Reseller pricing of low-end certificates is about the same cost as a domain. From Namecheap and elsewhere.
That said, I didn't know about this, and forgot to set up SSL at one of my domains. I didn't much care, but my reaction to this is pretty much "Oh, so that's what Google is bitching about. Okay."
This is much ado about rather little.