It's possible to build a computer for $230, but it's not going to run very well. If you're just looking for a cheap upgrade from a (very) old computer and don't mind paying a bit extra, this might work:
Of course, that's without an OS, so add $100 for an OEM copy of Windows. If you have an old computer you don't mind gutting, you can take the disc drive, floppy drive, and hard drive from it and get a graphics card instead of those (maybe a 6600?)
That's the cheapest I can get it, and it's not going to be real good.
no, not really possible to build a gaming machine on that budget unless you already have several major components. the bare minimum you could have for a gaming machine (from new parts) would be a 40gb drive, cheap motherboard either s754 or AM2 and a ~3000+ sempron. not sure but by my calculations that will set you back at least $150 (estimating an australian price and estimating a conversion XD so forgive me if i am wrong) then you would have to spend at least ~$50 on memory. no way does that leave any where enough for a lowend graphics card and remaining components