Desktop Computer Packages - How much does it cost to build a cheap pc?

How much does it cost to build a cheap pc?

I also want it to be fast.

Well, I would hope that it would cost cheap. There is no "cheap" when building a PC of any real use.
Go around to junk yards, repair shops and anywhere that outdated computers end up. You can get a lot of free or very "cheap" parts that way.
that depends on what you want it for. i built a gaming pc for around $600 and thats with a $250 video card. just for everyday things i'd be surprised if you couldnt do it for $300-350 and if you really find the best deals and build it yourself $250