Limit: $600
Just need a tower, no keyboard, speaker, monitor, ect.
Also, how much do you really save when you build your own system as compared with a pre-built tower from a company like HP? I know Dell is overpriced bullshit with fancy colors, but HP looks relatively solid.
I know overclocking saves you $$, but what else do you get? Are home-built systems any more or less reliable? How much do you really need to know to build a system, common sense and follow the instructions, or do you need like, soddering irons and stuff?
Building a computer is like building legos. It's ridiculously easy. Just don't do it while intoxicated. Touch the case frequently, especially when handling the CPU and motherboard. Try not to touch the cpu much (handle it by the corners). All you might need is a phillips head screwdriver, if it isn't included with your stuff.
Overclocking doesn't really save money, it increases performance. At least, I wouldn't consider overclocking as an option to save money. You save money on the middle man, and the assembly. What you DON'T save money on is the OS, which is typically where the OEMs make their money. That's why smart people get it for free in some way, shape, or form.
Reliability has little to do with the hardware, but the software, and how well you keep it up. Obviously cheap hardware will be less reliable, but even the cheap stuff has to work for them to make money. A lot of the time, OEMs put in random crap, which makes them cheap. Apple and Alienware are two companies which make sure good hardware goes into your system, but they charge you an arm and a leg for it.
As for the build, what are we looking at?
Case, mobo, PSU, CPU, GFX, RAM, HDD, Optical drive? If you can reuse an old Optical drive and HDD, you can save quite a bit, or get that much better a computer. $100 goes a long way, but it's important to set limits when buying, or else you'll just keep tacking on more money. If you need an OS, you'll have to either buy one ($30 for OSX or win 7's student discout) or use some form of linux/freebsd.
"Parliamentary inquiry, Mr. Chairman - do we have to call the Gentleman a gentleman if he's not one?"