Our website has a SSL certificated registered for the url www.limitedgoods.com

The issue is if someone enters just limitedgoods.com the SSL certificate will work but the user will get a message from the browser notifying them that the website is not the same as the certificate....
As a band aid I make the index.html (or home page) redirect to www.limitedgoods.com/home.php. It works but I assume there is a smarted and better way of doing this without buying a certificate for both urls. Thanks.

-Jeremy

Nope, there is no other way then how you've done it. You created an SSL cert for a specific domain, and the domain typed in must match the domain on the cert exactly to avoid the warnings.

so I assume that websites that DON'T redirect and open with the default page need to buy both certificates? Does anyone know if the page loads slower with a redirect?

Either they buy both certificates, or more commonly they will purchase a wildcard ssl certificate. A wild card certificate allows you to secure anything.yourdomain.com with one cert.

... or people make it easy for themselves and buy a cert for a subdomain such as secure.youromdain.com and then setup a cname dns entry so that it points to their main site.