[ithkuil]

self-signed certificate will just make your user furious, because recent browsers display very annoying alerts (especially firefox).

self-signed certificate will allow you to encrypt, but it's not secure.

Unfortunately you are bound to get a certificate from "vendors" that ship bundled with the major browsers (if godaddy sells you a certificate then it's ok).

Anyway, just a link for an utopic world http://www.cacert.org/. I don't know if something like cacert would work in the real world, but certificates are about trust, not about money.