If you build one yourself, you only save money by not adding certain accessories that storeshelf computers force on you. If you don't want windows, why pay 300 for it? If you don't need a 3.5 inch disk drive, don't buy one. It's things like that that'll save you money. Custom computers are good in that they give you exactly what you need.

For example, on the custom computer I'm saving for, I'm knocking 300 off the price for not using Windows. Linux is free, and I haven't found a single area that Linux *isn't* better than Windows. That 300 can go towards buying a higher quality motherboard, or graphics card, and not Bill's wallet. I don't need a DVD drive on my computer since I have a VCR style DVD player that does just fine. However much the built in DVD players cost will be knocked off of the price of my computer, and I can put it towards a higher quality processor or something. I don't use my 3.5 inch disk drive, ever. That's another small sum of money saved. I don't play solitaire, or any of those other preinstalled games, nor do I use any program besides a word processor and an art program. I'm sure they add to the price of a shelf computer, and I'm sure not having them on my new one will save me money. That's how custom computers save money.

If I were to home-build a computer with the exact same components as a store model, then besides being stupid, I'd be spending more money. Buying stuff in bulk saves retailers money too.