The Wolf Link amiibo is needed to even get to the place where the item is located. There is a third wallet upgrade in the game known as the Colossal Wallet that can be found only in the Cave of Shadows. You must have first acquired the first two wallet upgrades from the bug hunting sidequest before being able to get the Colossal Wallet. I recommend waiting till you have all the Heart Containers since you'll be running a huge gauntlet for this. Use the Wolf Link amiibo on the "Collection" screen during gameplay and choose to save the game and enter the Cave of Shadows. It will take three trips to get a shot at the Colossal Wallet and you'll be stuck in wolf form for the entire trip to the dungeon. Midna will not let you transform back cause you're required to do it in wolf form. After the first two trips to the Cave of Shadows you'll be able to go through the rest of the rooms to the end. Once you clear the last room drop down to find what will look like the same kind of cloud that the Great Fairy is enveloped in when you reached the special chambers in the Cave of Ordeals. Talk to the one there and you'll be given the Colossal Wallet for making it there. This wallet upgrade increases the max Rupee count to 9999.