Add a new dynastic rule, call it Trading with the text

At any time while an @ is on an even dungeon level they may trade 4 items in their inventory that are not ranged weapons for 1 item in either the basic weapons, armor, or potions table. It has an enchantment of 0 where applicable. With the exception of spellbooks, if an @ receives a ranged weapon this way, they receive 2 more of that ranged weapon.

At any time while an @ is on an odd dungeon level they may trade 2 items in their inventory that are not ranged weapons in order to Find Treasure.