You will want a secure server certificate if:

You want your customers to transfer confidential information using any form of your domain name, for example, yourdomain.com or secure.yourdomain.com, etc. Certificates are issued on a per-domain name basis and provide confirmation that the domain being visited is owned by the company listed in the certificate. It is highly recommended that you obtain your own secure server certificate; it is the only way your customers can know that they are doing business with your company.

You will not need a secure server certificate if:

You will be using someone else's certificate. This will apply if you use the shared secure server offered by FutureQuest^®, you use the shared secure server offered by a third-party online store and shopping cart service like RS Mall, or you use the shared secure server offered by your payment system/gateway that usually is included with your merchant account (like Authorize.net). Remember, if you do not have your own certificate, your customers will not be able to confirm that they are doing business with your company. For example, if you use the shared server certificate offered by FutureQuest^®, the only thing that can be confirmed by the customer is that FutureQuest^® is who they claim to be.