Human-related Costs
Design
High quality design can be very expensive, and TYPO3 can take on board virtually any design, from more-or-less any source, which need not be expensive at all.
Configuration and Development
TYPO3 is a development framework, and in addition requires configuration. A great deal of pre-existing development and configuration has been added to it by its development community, and these are made available free-of-charge both as functional add-ins, and as a basis for further development.
The existence and availability of this body of work can considerably reduce development costs, and the existence of known developers for extensions means that there is a large pool of people who can carry out paid development work if necessary, often as a development of pre-existing projects.
Similarly, by using the css framework YAML as the basis for the implementation of design work, we start from acessible, standards-compliant models which are flexible enough to support virtually all real-world layouts, while being cross-browser compatible.
Adding and Originating Content
All the software that is actually needed for an editor to contribute to a web page, or for a manager to commission it, is present on the web server. Input of data is through the familiar processes of form-filling and using a word processor, or by cutting and pasting or import from software on the local desktop.
Overall there is a consistency of approach to adding information to the site, so that once someone has used one extension, they are likely to find another straightforward.
In addition, the editing environment for a given editor can be simplified to avoid confusion and clutter, and maintain the security and integrity of the site.
Taken together, this means that the people who add the content to the site almost certainly have the skills required to do so, and, although they will probably require some training, this will be minimal.
Having said this, it is important to plan and assign resources to allow people to be able to contribute to the site.
Similarly, many organisations have a great deal of content which they have in digital format, and want on their site initially. It is frequently more effective to outsource this initial loading.