As an addition to this little PSA, I'd like to truly show you how easy it is to build a computer. Newegg has provided us with excellent video guides that demonstrate every step start to finish. PART 1 PART 2
It really is no ordeal. Yesterday I built a computer for a family friend and made $50 off of it. From when I started unpacking parts to when windows was fully running, took a little under 2 hours. It was fun, too. That's the full extent of being in the know about computers. Profit.
On the other end of the spectrum is ignorance. My friend's stepdad, who I was going to build a computer for, instead decided to get his iMAC G3 fixed for $190. The G3 is a computer from the late 90s that wouldn't sell for 1/3 as much as he spent. Stupidity is the businessman's boon, and when you can't make an educated buy you WILL waste money.