That depends on how you want to do it. Big pieces eat up yardage. If you use two or three different colors and have smaller parts because of that, it would be different than all one color. All one color: 1 1/2 to 2 yards for each bucket seat, one yard for each door panel, 1/2 yard for the kick panels , 3/4 yard for the console sides and about 1 1/2 to two yards if you do the headliner. 9 or 10 yards will do it easily.
No one lives forever, the trick is creating something that will.