As your character is fresh off of tutorial island, there isn’t much you can do to make money until you get high level combat or smithing. The most obvious route by experience players is to Rambo the 10,000 coins in the Stronghold of Security.
Unfortunately, a level 3 account can easily get dropped by high-level monsters. This makes gold making even more limited as a fresh HCIM without making it extremely tedious.
Another popular, yet risky, method used go to the ruins in level ? Wilderness to get a full invetory of steel platelegs to sell to vendors. Unfortunately, gold farmers have locked down this spawn so this method isn’t so viable. These gold farmers are using a similar method as shown in this video.
There is one spawn outside the wilderness that can make quick gold thanks to the abundance in Free-to-Play worlds that were added to the game. I am referring to the Iron Mace spawn found the the guard hut in Edgeville.
Just a few seconds away from the spawn
This mace has a very low value on the grand exchange and makes for a horrible training weapon. This is why it is overlooked by normal players. Fortunately for ironmen, this spot has little competition and sells to the nearby General Store for 25 coins.
The idea is to fill your inventory with maces and sell one at a time to the General Store while hopping worlds. It is tedious but a full inventory will net 700 coins. Within a few inventories, you should be able to buy most of the starter items that you need as a level 3.
Note: This method isn’t really viable for regular accounts. Even collecting bones in Lumbridge would be significantly faster than selling iron maces.
With this newly acquired gold, I recommend purchasing an Event RPG and Chronicle from Diango in Draynor Village. For questing food, wines are sold in the same town.