When you get the Chief Fisherman's' Daughter, go to the beach where she goes to find the Aquamarine. When you fight the little Jewel Leapers. they give you the stones that are needed to make Runes. Get a large number of them and some gold, then go to the Rune-Makers shop. Refine the Gems into Runes, which cost 230 gold. When they are refined, the Rune Shop will buy them back for 400 to 500 gold. Repeat this trick as much as desired to obtain an unlimited amount of gold.