Efficiency

Level 5 of the Dungeon
(0, 0, D:5)
  15 gold pieces
(12, 9, D:5)
  19 stones
(19, 0, D:5)
  a book of Necromancy
(21, -2, D:5)
  a potion of attraction

Level 6 of the Dungeon
(0, 0, D:6)
  13 gold pieces