None.
The point is that the service we provide is complete, so you really should not need additional services. We are not in the "bait and hook" business of providing a cheap offering then adding other services. What we offer is a complete service that works with you to design and build the website, then shows you how to add articles yourself, passing on all of the passwords and other information so that you are in control.
Of course, there may occasionally be exceptions to this. If you want some special feature or if you come back to us after ten years to ask for some changes, then we will discuss how we can help, and how we can do so as cheaply as possible. Our aim is however not to trap you into paying for additional services or features, but to build a completely functional site that you can edit very simply for a single one-off fee.