Sell Treasure
You may not realize this, because Final Fantasy XV never really makes a big deal out of it, but you pick up a lot of treasure as you play the game and defeat enemies. Even if you don’t go to the treasure locations marked on your map, chances are that you have a ton of it in your inventory already. Hunts each drop a piece, plenty of common enemies drop them, and you’ll find quite a bit laying around the world as you explore, not even marked on the map as treasure. You can sell all of it.
While each piece has a different value ranging from as low as 50 Gil all the way up to thousands per piece, they all add up. Simply head to any vendor in the game and choose the “Sell” option to offload all of the junk you’ve collected. You’ll earn more Gil than you know what to do with faster than you can say the words “Chocobo Lure.”