I built my computer 2 years ago for just over $500 (minus a HDD, monitors, and DVD-ROM, which I already had, but if you have a computer at all you probably already have a lot of the minor parts you'll need) and it runs the beta fine. If you want a laptop that'll run it on medium-high settings, or a desktop that'll run it on 3 monitors on high settings, you might be talking about a $1500 machine, but if you just want something that will run the game at a playable level on low to medium settings you can get by pretty cheap.
Of course, if you're willing to wait for a while you could always get a used PS3 for cheap and play it on that.
Edited, Aug 29th 2010 9:25pm by khorbin
"So farewell hope, and with hope farewell fear,
Farewell remorse; all good to me is lost.
Evil, be thou my good."
-John Milton, Paradise Lost
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