Negligible additional cost to new sites - Creating a new website that is accessible requires no new hardware and only minimum investment in testing and development software. Competent developers can implement W3C guidelines with no additional training, although there are seminars and guides available.
Low cost to existing sites - Making an existing website accessible costs on average under 5% of total development expenditure, although this cost is highly variable and depends on the size and infrastructure of the site (e.g. a site built with style sheets is much easier to make accessible than a site with stand alone pages).
To return to main window, close this window via the menu option in the file menu