rear vent window?

If you mean the quarter glass window at the driver's side rear, a new window should be around $200, according to my dealer. The reason I know this is that the same window was busted on my VX a few weeks back and they were the first people I called.

I called the Isuzu/Hyundai salvage guys and bought a window from them for $125. $45 to install using a local glass installer.