The Mask Quest begins in Hyrule Town at the Happy Mask Shop (the strange-looking building in the photo above). This shop offers a
new and relatively simple concept. The shopkeeper lends you a mask that you will try to sell by wearing it and talking to people
(note that their dialogue changes depending on your mask). Once someone is willing to buy it, they give you however many rupees they want
and you go pay the shop owner the face value of the mask (which you see when you borrow it). Depending on how many rupees you were given,
you can make a profit or a loss on the sale. Each time, the shopkeeper will offer you another mask to sell.
The Fox Mask is a trendy mask that people find cute, though the guards find it ugly. The one who buys it from you is in fact a guard (the one who had asked you to find it for him).
He guards the entrance to the path of peril at the very top of Kakariko Village and will buy the mask for 15 rupees (5 rupees profit for you).
The Skull Mask is a mask that scares people (though in my opinion, they're just pretending to please you) and must be brought to Skull Kid in the Lost Woods (just to the left of the entrance).
Before selling it to him for only 10 rupees (10 rupees out of your pocket), go to the Swamp Theater's mask-making contest in those same Lost Woods to get more Deku Sticks.
The Spooky Mask is not very popular, people don't like it much.
You will still find a buyer in Kakariko Village — the small child who plays the Graveyard Game in the cemetery. He will give you 30 rupees, which is the price of the mask.
The Bunny Hood is very cute and people love seeing you wear it. However, you won't find any buyer in the villages.
The buyer is out on the field and spends most of his time running.
The marathon runner, as he is called, will fill your wallet in exchange for this mask, which could be up to 450 rupees profit if you have obtained the Giant's Wallet (30 Skulltulas).
Note that this runner only stops occasionally to rest and won't talk to you while he is running.
You'll need to follow him until he stops to rest and then speak to him at that moment.
He rests in the Northwest of the field when the sun sets.
The Mask of Truth is the goal of the quest, the king of masks, the Holy Grail. Its powers are tremendous. Talk to people while wearing it to learn their deepest thoughts.
Look at the Gossip Stones to obtain secrets of varying importance. Additionally, you can use it to return to the Swamp Theater and obtain more Deku Nuts.
The other masks are useless but Link will look pretty cool wearing them.