Another way to save a ton of money is to purchase a motherboard that has on-board components. An on-board component is a feature that your motherboard has built "on-board."
Do you see all of the plugs in the back of your computer, such as the speaker output, video output, etc? Those are where the on-board components can be found. This concept is a double-edged sword because although they are convenient, they often become the first outdated part of your PC.
The main types of on-board motherboard components include audio, video, Ethernet, USB, and Firewire.
If you're looking for the most economical computer, for use with simple tasks such as word processing, then on-board audio, video, and USB 2.0 should be fine. Firewire is another form of file transfer that will probably not be needed by most users. It is faster than USB, but I've never had a situation when USB was not sufficient.
Here are some more details about the various on-board elements and when they are appropriate for you:
Unless you're on a very tight budget, you should get a motherboard WITHOUT on-board video. The technology in this arena is rapidly changing and you'll find that your on-board video will quickly become outdated and inefficient. A separate video card is ideal for people who want to play video games & watch movies on their PC.
Only audiophiles can tell the difference between the sound quality of a separate sound card vs. on-board audio. The only time I feel a separate sound card is needed is if you'll be hooking up a digital surround sound system to your computer
3) USB 2.0
This is a must have for any computer! If possible, opt for USB 2.0 over USB 1.1 because version 2.0 is about 40 times faster. USB is becoming increasingly important with the use of plug & play devices such as digital cameras, scanners, printers, etc.
This is not needed by most users, as it is an alternate form of data transfer. It's similar to USB, except much faster and efficient. Unless you know you'll need this, I wouldn't pay extra for it.
Another note is many motherboards with on-board video / audio come with an APG (video) slot or additional PCI cards slots. So if your on-board hardware becomes obsolete, you can always add on to your current system. The only downfall of this method is you must sacrifice some PCI card slots that you had plans for other uses.