CMS (content management systems) are basically website pages that are set up to be editable by the owner of the website. The owner buys a website and, through a private admin area, are able to update the website themselves without a web designer. It eliminates long-term costs and puts the owner in control.
The owner can add pictures, headings, links, etc. with the admin panel. OwnDesigns.com offers CMS pages at the same price as regular pages, $65 per page.
With content management, the owner can add images, change paragraphs, show their latest specials, update dates and times, and do what they want with their website. The graphical layout stays the same, but the content is fluid. It's especially cheaper for owners who need to often update their pages.