You can make money by smelting gold ore, turning it into gold bars. It's highly recommended to set up a bank preset with 28 gold ores. The preset should then be configured to be one of the two single-keypress buttons (which can be activated by pressing '1' and '2' respectively). It is also highly recommended to use a portable forge to smelt the gold, as you both earn more experience, and have a 5% chance to get a second bar, increasing the profit.The Lumbridge combat academy on world 3 usually has a portable forge up.