Welcome to Termina

Powder Keg:-
You can buy this for 100 Rupees after you complete the seller's test where you have to carry one to the Goron Race Track to clear the entrance, but if you are a bit tight on dough you can buy one from a Goron in the Clock Town Bomb Shop for 50 Rupees if you are wearing the Goron Mask.

Bottles:-
Link can carry a total of 6 bottles (no, not the mole from Banjo Kazooie -N. Knight), here's how to get 'em:
1-Get the medicine for the sick witch in the Southern Swamp, it will come in a bottle which is yours to keep.
2-Complete Romani's notebook entry at the ranch to receive your 2nd bottle, which comes with milk.
3-Get a bottle filled with Gold Dust in you win the Goron races.
4-Win the Beaver Races(hookshot is essential for this bottle, as you need it to get above the waterfall where they are held) for your 4th bottle.
5-Finish the cemetery side-quest for the 5th.
6-Complete Madam Aroma's notebook entry to get the last bottle

Moon Tear:-
If you can remember the Moon Pearl from A Link To The Past, well, it is nothing like it. But it will be very useful on your journey.
Maps:-
Link can buy maps of the different areas from a 35-year old, fairyless elf man called Tingle. He's quite a strange character but helpfull nonetheless. Areas on your map sub-screen, will be clouded over until you buy a map of that area, they also bring up the map display in the bottom right-hand corner if you have a map of that area.

Rupees:-
The money system in Termina, Green=1, Blue=5 Red=20, Purple=50, and Gold=200.

Piece of Heart:-
Collect 4 of these for a whole new container of life.

Dungeon Map:-
Just like in Ocarina, guides you through the dungeons.

Compass:-
Helps you guide your way through dungeons, showing you where treasure chests are and it also shows you where the boss is.

Key:-
Opens locked doors in dungeons.

Boss Key:-
You will need to collect this if you want to fight a boss as it is the only key that will open the door to his lair.