you mean using the power supply that comes with the case? as i said before, 20 bucks is cheap, i would not trust the power supply either, i would up it to a name brand 350+ watt psu at least. if money is truely a priority, get the case and upgrade the psu. if you could save up 60 bucks or more, i would go to newegg.com and check out some better quality cases w/psu's.
EDIT: i don't even trust my power supply that came with my Raidmax case, it does it's job well and it's a 420 watt. but with me overclocking my chip and my 6800, i plan to upgrade my psu soon.