Complete the Lunar Diplomacy quest, Castle Wars Balloon and access to more battlestaves by completing Varrock Diaries or the 66 Magic. Making Battlestaves is a popular method to earn some money. In addition to RS Gold the money you earn, you also gain experience in two areas namely Crafting and Magic. This method of making gold takes a lot of work however in the end, it's worthwhile than making traditional Air Staves.
In the beginning, you should include the most essential items in your collection - the The Graceful Outfit, Fire Staff, Ring of Duelling and the Anti-Dragon Shield. If that's not enough, you'll also need to collect cosmic runes, logs and the most effective remedy that you can afford. The rest of your inventory must be filled with non-powered orbs. If you have less than 70 Agility, you will not be able to make use of the shortcut, so ensure that you bring along the Dust Key.
Begin with The Castle Wars and take the balloon to Taverley. Once you are on the site, head towards The Fire Obelisk. It requires at least 70 Agility (80+ recommended). Charge all of the orbs you've brought with you and then teleport back to Castle Wars. Castle Wars to repeat the procedure.
Once you're done the charging process, create Battlestaves from the orbs, and then make use of High Alchemy to turn them into gold. As you are below 70 Agility, this process is very run intensive , you may have to do doing additional tasks like fletching or alching. This is something you can do during the time between runs, while trying to Buy OSRS Gold recover your endurance.