That's a bold statement. If you have no idea what you're doing, you can very easily lose out in terms of both price and quality, and if you try to save money by recycling old parts, you'll likely get what you pay for.
Well, I wouldn't recommend my 70 year old aunt, who couldn't care less about the workings of a computer, to build a custom gaming rig herself for her e-mailing and digital scrapbooking needs. But Ncmark seemes to have the motivation to learn about the noble art of computer building.
When I said "recycle old parts", I mostly meant parts like the case, DVD-unit, keyboard, speakers, screen, mouse and other peripherals that has a much longer shelf life than graphics cards and the like. I have several old workhorses in and around my modern computer that has been around since the 90:es and still perform as well as what you could buy new today.
Then again, a person who knows nothing about computers would likely end up with a real crappy pre-built one anyway. Those I see in stores are ridiculously overpriced, ridiculously overpowered in areas that yield high numbers and inflates the price (like the amount of RAM or the GHz of the processor) but underpowered in areas that really matters, with weak graphics cards (with huge amounts of video RAM to appear powerful) that bottlenecks all the good components. Sure, auntie 70 years old wouldn't need a good graphics card, but she wouldn't need 8 GB of RAM either.
Here is an example of a computer sold where I live. I suppose the specifications don't need to be translated to be understood: http://www.elgiganten.se/product/datorer-till … stationar-dator
That is what most average Joes who believe that "more expensive is better" would end up with. The price is about 1400 dollars...
And on the matter of quality, it's pretty much a non-issue. To put it simply, hardware has become so cheap that it's hardly worthwhile for a company to produce crap, and so there just isn't much crap on the market anymore. And amongst the low-quality parts that do exist, you're not likely to find them in prebuilt machines. Manufacturers tend to want their machines to last awhile, because warranty claims aren't profitable.
I was mostly speaking from my experiences with my dad's 6 years old Compaq Presario, which happens to be the worst computer I've ever seen. The specifications are all right for it's time, but they cut corners in every way imaginable. The cooling fans (Delta) sound like vacuum cleaners and suck dust inte the computer like vacuum cleaners, the CPU cooler is a block of aluminum that overheats from the strain of just opening the web browser and makes the cooling fan spin at 100%. The over heated CPU cooler also made all the capacitors in it's vicinity age prematurely from the heat it radiates. I'd like to replace the cooler, but I can't since it's glued to the processor.
Then I had to drill new holes in the case when I wanted to fit a new PSU, because the case wasn't ATX compliant. Just about every other component is OEM with proprietary drivers that makes it hard to fit them in another system and lowers their second-hand value if I were to sell them after an upgrade. Then my dad paid extra for features he has never ever used, like both a normal DVD-unit and a DVD-writer, a SD-card reader, a modem. And then there were all the bloatware that took me hours to identify and uninstall...
I could go on, but I think you get my point.
To build your own computer from scratch might require an initial investment of learning, but once it is finished you will have a computer that does what you want it to do and that can be easily upgraded whenever your needs changes or technology advances. And if you recycle some old parts and buy some parts from Ebay it will be much cheaper than to get every component brand new in a pre-built system.