Teleport With Command

[Jamezo97]

Hi all,
Is there a way, to make a trigger, that teleports you to a certain point. Because I am making a map, and only want the player to be able to do something (buy stuff from a shop) if they have befriended someone at the start of the game. If they haven't, when they talk to the shop keeper I want them to teleport back outside.
So all I want, is to have a command that teleports a player to a certain place on the map.
Does anyone know a command that will do that?

Thanks