Efficiency

Level 5 of the Dungeon
(0, 0, D:5)
  3 large rocks

Level 6 of the Dungeon
(0, 0, D:6)
  a scroll of identify
(3, -1, D:6)
  the +7 hunting sling of Checks and Balances {vorpal, rF+ rC+ rN+ Dex-2}
    Any ammunition fired from it inflicts extra damage upon your enemies.
    
    Dex:       It affects your dexterity (-2).
    rF:        It protects you from fire.
    rC:        It protects you from cold.
    rN:        It protects you from negative energy.
(12, -10, D:6)
  9 gold pieces