as you guys probably already know, i'm no mechanic, and i don't pretend to be one, and i need some help. when i start my x up, it will rev to about 500 rpms then it'll bounce back and forth between 200 and 500, and then it dies. what could be the cause of this problem, and how much am i looking at to fix it?

Sounds like IAC valve either clean it or replace lots of info on here about it.:D