So I looked through the forums and it seems this question gets asked a lot.
How do I setup wireless over certain distance?
But I couldn't find an easy cheap answer so here is my exact situation.

My parent's house is 300-500 feet away from my house, and I want to use their internet so I can play xbox 360. I have a good LOS. What is a good, CHEAP solution?

They have cable internet and ideally I would like to keep every thing inside their house(they don't want me strapping a huge antenna on the side of their house). But if its small and cheap I might be able to do it.

I am confused on a few points:
Can I just get a high powered antenna on their side and just use the wireless card for my xbox, or do I have to have a bridge on my side as well so I can send good signals back?

I would be eternally grateful, if someone could post exact hardware that would work for this. And if it cost under $200 I would be even more grateful( I would of thought grateful is spelled greatful, who knew).