Efficiency

Level 6 of the Dungeon
[Shop] Naudax's General Store
  (Shop contents are unknown)
(0, 0, D:6)
  19 gold pieces
(1, 19, D:6)
  7 gold pieces

Level 7 of the Dungeon
(0, 0, D:7)
  a +0 flail
(1, -3, D:7)
  a staff of fire