Here are most of the steps in creating a professional document:

  research, authoring, book design, page composition, copy editing,
  art creation, proof reading, indexing, permissions, cover design.

Notice that there is nothing in this list on publishing, printing,
manufacturing, distributing, warehousing, or marketing.  All the
creation steps have to be completed regardless of the output media
and distribution channels.

Of course, the desired output media will affect the design and creation
process.  For example, image resolution requirements for web publishing
and art books are not the same, color matching is more critical for
coffee table books than for web publishing, PDF formats offer
capabilities that print formats do not, etc.

The bottom line is that there are no significant differences between
creating a professional document for PDF format and printed formats.
In fact, many corporate documents are created with the knowledge that
they will be distributed via multiple media such as print, web, or
email.  Examples include annual reports, sales brochures, and product
manuals.

As far as cost, the creation and design process can be accomplished
using professionals specialized in each of the steps listed, in which
case costs can be in the tens and even hundreds of thousands of
dollars.  On the other hand, the same tasks can be accomplished for
virtually nothing (except time) using tools and skills already
possessed by the creator, such as Microsoft Word, a competent drawing
program, and a digital camera.

Conversion to PDF format can be accomplished by software available for
$0 to $100.  The higher end PDF creation tools allow for capabilities
other than static display such as hyperlinks.

Jim Divoky