They can be found in wilderness city on left side, in the Varrock sewers dungeon, Draynor Manor 1st floor. The sewer variant is aggressive and will attack on sight, while ghosts living in Draynor Manor don't attack until provoked.
Gold:
Min0 - Max
Loot:
don't drop loot.
Notes:
Ghosts are more dangerous than skeletons. They drop a orange key in "Melzar's Maze"