Where can I get a new video card for my computer, cheap?

I want to play the Sims 3 and it says I need a new video card and my mom is being a butt about it.

So where can I find one cheap and I how do I know it's right fir my computer?|||You will need to know what kind of video slot your computer has, pcie or agp. The card should be directx 9 compatible and you will need at least 1gig of ram to play Sims 3. Start by looking in system information to see what your computer specs are. Try Tiger Direct or Newegg!!!|||You could try Newegg.com. As far as knowing if its the right one, you would need to provide the specs of your system.