You can add SitePad as an add-on for any new Web Hosting Plan.
Keep in mind, that changing to SitePad from within an account without it, means you will have to move servers (clouds). This will change your account IP and your login URL for some sections. We will send a new welcome email once it's changed.
We also suggest starting your account over to a new one if you're adding SitePad. If you have old files or databases on your account, they can cause a conflict with the site builder. Just let us know if you want to start the account over and we will do this before the transfer.
Once you choose to add it, it will take about 24 hours to complete the change. Please add a ticket requesting this if you want to add it to an existing account.