Efficiency

Level 5 of the Dungeon
(1, 3, D:5)
  a +0 trident
(10, 3, D:5)
  a +0 hunting sling

Level 7 of the Dungeon
[Shop] Mij Xasch's Jewellery Boutique
  (Shop contents are unknown)
(0, 0, D:7)
  a scroll of teleportation
(11, 20, D:7)
  15 sling bullets