This article contains several errors.
Firstly, Apple's mini-DVI to DVI cable is $19, not $29 as stated in the article.
http://store.apple.com/us/product/M9321G/B?mco=MTIxODk3Mw
The Mini-DisplayPort to DVI adapter, however, is $29. As of this writing, it is not available from third parties at all, let alone for cheaper.
The $99 Mini-Displayport to Dual-Link DVI adapter is only necessary if you're hooking a new MB or MBP up to a monitor with resolution greater than 1920x1200, like the 30" monitors from Apple or Dell, which have resolutions of 2560x1600. Chances are, if you're willing to spend $1799 for a monitor, an extra hundred will not hurt you too much.
Currently, If you're hooking up your new MB or MBP to an HDTV, you don't need the Dual Link adapter for $99, you need a mini-DP to DVI adapter for $29, as well as a DVI to HDMI cable.
Finally, before everyone gets too bent out of shape, they should read this article:
http://www.maximumpc.com/article/the_myth_of_an_hdmi_displayport_standoff