Once you have an SSL certificate installed for yourdomain.com (the certificate is specific to the domain name), you can simply switch between secure and non-secure using the url. If you are on a shared hosting plan, using SSL does require a dedicated IP address.
http://www.yourdomain.com/somefolder/index.html
https://www.yourdomain.com/somefolder/index.html
These two url's would cause the same web page to be displayed, but the 2nd would be sent encrypted using SSL.
For your example, you would simply have a product page -
https://www.yourdomain.com/somefolder/productpage1.html
SSL encryption only effects the data that is sent/received and not anything on the actual web site.