i built my computer for about 500$ a year ago off of newegg.com and i just recently built my cousins gaming computer(budget) by buying the parts directly from tigerdirect, we went their bought the parts got back at his house around 6 and we had it running in about 2 hours with windows and everything installed.
really building a computer is not as hard as some people think it is. i would look into doing that its a great skill to have, it will save you tons of money and it gives you a fun project to do.
my computers stats that i built last year are:
4 gb ddr2 ram
250gb hdd
3.0 ghz duel core amd processor
and a 512mb 9800gt nvidia graphics card.
if i was you i would probably go with a ddr2 setup rather than a ddr3 as it is new technology more expensive and unnecessary unless you are going to use that computer for something more than what you plan on doing. also amd is the way to go with processors if your looking for a budget build. they are easily overclocked to make their performance great if your willing to put in the time to learn too overclock.
also i would not recommend dell they are extremely over priced and i heard they glue their parts into place ( funny thing is im typing this on a dell laptop that i got for free for signing up for comcast
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