This Page explains the uses of link's items
Deku Stick-Can be used as a weapon but it breaks very easily. Usually used to light torches or burn other objects;you can light it by bringing it near a lit torch. It can be bought in a Shop, but is found around the forest or other places for free.
Fairy Slingshot & Deku Seeds-Used to defeat distant enemies. Requires Deku seeds as ammunition. It is found on the second floor of the Deku Tree. Deku Seeds can be bought only in the Kokiri Shop, but can be found almost anywhere.
Fairy Ocarina-Ocarina used to play the mysterious songs of Hyrule before you obtain the Ocarina of Time. Playing songs can trigger many things to happen during the game.
Boomerang-Used to defeat or stun enemies at a limited distance, does not require ammunition. It is found on the first floor of Jabu Jabu's Belly.
Magic Beans-Plant them in any square spots of soft soil you find. You buy them from the man in Zora's River chomping beans. They start at 10 rupees and increase by 10 every time you purchase one (there are 10, so you end up paying a total of 550 rupees). Once you become an adult the spots of soil where you planted a magic bean will turn into floating beanstalks that take you to useful places.
Deku Nuts-Stuns some enemies when thrown. It can be bought almost anywhere and found almost anywhere.
Bombs-Used to open weak walls, destroy light colored boulders, open holes in the ground and other things. It can be bought in most stores and found in many places. You can't use, find, or buy bombs until you get the bomb bag which is located on the second floor of Dodongo's Cavern.
Bombchu-New type of bombs that races along the ground, up walls and even on ceilings, after a few seconds it explodes. They can be purchased in the Bombchu shop when it opens (the empty shop in the back alley of Hyrule Castle Town), you can also get them as a prize in Bombchu Bowling Alley when it opens or find them in treasure chests (one of the more scarce items in the game).
Din's Fire-When used, it surrounds Link in a ring of fire and kills all enemies in the area. It uses 6 points on your magic meter (you need to have a magic meter to use it). If you only need to light one or two things, the Fire Arrow saves you magic, but if you are lighting many things at once this is more efficient. You get it in the Great Fairy's Fountain at Hyrule Castle.
Farore's Wind-It can only be used in dungeons (Deku Tree, Dodongo's Cavern etc.)When you use it once it creates a warp point, when you use it again you can either dispell (delete) the warp point that you created or warp to the warp point. It uses 6 points of magic power (you need a magic meter to use it) It comes in handy in places like the Water Temple where you have to raise or lower the water levels. It is found in the Great Fairy's Fountain in Zora's Fountain.
Nayru's Love-It creates a diamond shaped blue shield that surrounds Link and makes him invincible to all enemies for about two minutes. It uses 12 points of magic power each use. You cannot use anything else that uses magic while Nayru's Love is in effect. When it is about to run out it will blink. It is found in Desert Colossus in the Great Fairy's Fountain.
Magic Jar-Used to refill magic meter. They come in two sizes (the bigger one refills more). They cannot be bought, they can be found in many places.
Ocarina of Time-Treasure passed down by the Royal Family of Hyrule. It has the same function as the Fairy Ocarina. When you retrieve all three Spiritual Stones and return to Hyrule Castle, Princess Zelda entrusts the Legendary Ocarina to you.
Lens of Truth-Used to see through fake walls and invisible holes in the floor and other invisible things, you can also use it to "cheat" in the Treasure Box Shop in Hyrule Castle Town. As you use it, it slowly consumes your magic (the longer you use it the more magic it uses).
Bottles-Empty bottles are extremely useful in your quest. they are used to carry things such as potions. They cannot be bought. See the bottles section on the homepage for information on the four bottles.
Hookshot & Longshot-It is one of the most useful items in the game. It can pull distant items towards you, or pull you to something (roofs, crates, wooden beams etc.). It does not require magic or ammo to work. The Hookshot is won after the "race" with Dampe, and the Longshot (which shoots twice as far) is found in the Water Temple in the room after you beat Dark Link.
Fairy Bow & Arrows-Similar to the Fairy Slingshot, but is used as an adult. Used to hit Long ranged targets. It is found in the Forest Temple after defeating the two stalfos on the second floor. The Arrows can be found or bought almost anywhere.
Fire Arrow-It is the same as a regular arrow, but it sets flame to most enemies and can burn other objects such as torches. It uses 2 points of magic power and 1 arrow per use (there is not a seperate inventory of arrows for it, it uses the same arrows as regular arrows). It can be obtained after you beat the Water Temple, you have to fire an arrow at the rising sun from the island with the dead tree on it.
Ice Arrow-It isn't that useful, you don't actually need it to complete your quest but if you want more adventure you can try to get it. It freezes some enemies on contact. It uses 2 points of magic power and 1 arrow per use. It is found in the Gerudo Training Ground in the middle of the door maze.
Light Arrow-Used to defeat enemies and dispell the barriers in Ganon's Castle. It is also the only weapon that can hurt Ganondorf. It uses 4 points of magic power and 1 arrow per use. Princess Zelda gives it to you after you awaken all of the sages (get all medallions) and return to the Temple of Time.
Megaton Hammer-It can break boulders (and statues in the Fire Temple) and can even open secret holes in the ground! It is found on the fifth floor of the Fire Temple.