What size surf board shoud a person who is 6 ft tall buy?

It depends on other factors such as weight, Surfing conditions and skill. A beginner should really start out on a Mini-Mal board at around 8ft in length if they are of average weight. An intermediate of average weight should be looking at using a Mini-Mal, Funboard or Shortboard of around 7ft in length and a professional would probably be using a Shortboard of around 6ft in length. The thickness, width and rocker of the board is also important when buying a surfboard so consult your local dealer before buying one.