My rack is a Thule setup with the regular square bars. I got it at a local bike shop on the one weekend they run a Thule sale.
It goes on and comes off within minutes, no drilling, etc, and uses special rubber feet where it contacts the car so it won't scratch or damage the car.
I ended up buying new because Thule comes with a lifetime warranty (not sure if that transfers when you buy used). Total with bike mounts/etc came to ~400. No one in my area was selling the right feet for the Focus either. But if you get lucky and find a rack on Craigslist that fits the Focus, you can save a lot of money that way.
Also, one note: Yakima had a recall for their 2012/13 rack setup. I'm guessing they have fixed the problem by now, but if you buy used, make sure it's not the old setup that had problems (Which I think were only issues if you got in a crash).