In the Castle, there is actually nothing to buy. However, after you obtain the key, you are able to obtain the following items from the treasure vault: Iron armor, iron shield, TNT, iron staff, saber, and a silver knife.
In Coneria city, you are able to purchase weapons, armor, items, and white and black magic.
Wooden Nunchaku, 10 gold (sell for 5)
Small Dagger, 5 gold (sell for 2)
Wooden Staff, 5 gold (sell for 2)
Rapier, 10 gold (sell for 5)
Iron Hammer, 10 gold (sell for 5)
Cloth, 10 gold (sell for 5)
Wooden Armor, 50 gold (sell for 25)
Chain Armor, 80 gold (sell for 40)
Heal Potion, 60 gold
Pure Potion, 75 gold
Tent, 75 gold
All magic costs 100 gold per spell.
White magic: cure, harm, fog, ruse. Black magic: fire, slep, lock, lit.Enemies in the area: