Hi Scott,
SSL and certs and getting it all working can be quite a bit to take in if you're new to this kind of "stuff".
When choosing a cerificate supplier, or rather signer, first take a second to think of the (intended) visitor's "need for trust".
Certificates are all about trust, it's the internet's way of showing your ID-card and letting the visitor know it's really you. The certificate issuer (CA - Certificate Authority) would be the company that issued your ID-card. As such, the CA should be someone the visitor trusts.
What does all this mean then? Well, a College might issue their own Student-ID/Teacher-ID cards. They'll work just fine on-Campus, but if you try them at your local bank, the result would probably be... less promising.
The same applies to certificates - you could fairly easily create your own CA and sign your own certificates. As long as your friends know about your CA, they'd trust it. However, a random visitor would most likely NOT trust this certificate.
It all comes down to trust.. Everyone trusts VeriSign, so everyone trusts a certificate VeriSign has signed.. hence they can charge quite a lot for their service. If you need Bank-grade trust, VeriSign is the way to go. If you settle for having encrypted communications without Firefox and IE barking, there's usually options you'll find more priceworthy.
Next, I think I scratched the surface on this in an earlier post;
Due to the mechanics of SSL, there can be only one certificate per IP:port combination. The hostname written into the signed certificate must further match the hostname ("reverse resolved") of the server - kind of like the photo of your ID-card or passport must look like you to be valid. Now, since IPv4 addresses are becoming a limited resource these days, more and more webhotels resort to these shared SSL solutions, or charge extra for a personal IP (sometimes called root server). Webhotels/serverhotels that offer personal IP's or root servers often act as a subsidiary signer for certificates at a lower cost compared to corporations such as VeriSign.
Soo, pointers (hope you made it all the way down here):First off, see what kind of services your current webhotel offers. Especially if they allow you to have your own IP address and use private certificates. If they can't let you have your own IP address, then you can't use your own certificate - regardless of whether you purchased it from VeriSign or anywhere else.
Secondly, check if they can help with certificate signing.
If you are a computer-geek like me, then you could download the OpenSSL software package (
http://www.openssl.org/related/binaries.html). This is a software package that allows you to create your own certificates, CAs, along with simple server and client programs to test them with. There are a few good documents on certificates, CA's and keys there too.
/Fredrik