Efficiency

Level 4 of the Dungeon
[Shop] Uxeir's Armour Shop
  (Shop contents are unknown)
(0, 0, D:4)
  a scroll of identify
(2, 5, D:4)
  11 stones

Level 5 of the Dungeon
(0, 0, D:5)
  8 gold pieces
(11, 2, D:5)
  a scroll of fog
(13, 0, D:5)
  7 gold pieces