How do you get good video graphics of a video game

If you are using an Xbox, PS3 etc... you can get a high def cable. (HDM1) But you need a certain outlet in the TV. Usually comes with flat screens.
If you are using a computer you can most of the time edit your graphics in the game's settings. But mostly with a computer you need an up to date graphics card which range from $60 and up in the $100+ range.