You'll encounter lots of items in the game. Some are rare and can only be found once. Some are very common and can be found lying on the ground. Some can only be bought at certain stores.

Items can be found on the ground in the shape of a little circle. To pick up an item you see, walk up to it and press A. The game will then tell you "(your name) got (name of item)!" There's no way to tell what an item is before you pick it up.

Sometimes, you can find items lying on the ground that are hidden. You either use ITEMFINDER or just sorta guess.
For example, on the S.S. Anne, a cook tells you that he saw a strange ball in the trash. You go to the trash cans. There are three. Walk up to one and press A. It will either say "There's nothing but trash here." or "(your name) got GREAT BALL!" If you get the first message, try a different trash can.

Here's a list, in alphabetical order, of all the items in the game.

	Antidote - Removes poison from a poisoned Pokémon.
	Found - Poké Marts	Price - 100
	Awakening - Wakes up a sleeping Pokémon.
	Found - Poké Marts	Price - 250
	Bicycle - Lets you get from place to place much faster than walking. You need it to go on the Bike Trail to Fuschia City. Get a Bike with the Bike Voucher.
	Found - Cerulean City Bike Shop	Price - 1 Million
	Bike Voucher - A coupon for a free Bike.
	Found - The guy in Vermillion City who likes to brag about his Pokémon.	Price - 0
	Burn Heal - Heals a Pokémon that is burned.
	Found - Poké Marts	Price - 250
	Calcium - Increases your Pokémon's Special points.
	Found - Celadon City Department Store	Price - 9,800
	Carbos - Increases your Pokémon's Speed points.
	Found - Celadon City Department Store	Price - 9,800
	Card Key - Lets you open doors in Silph building.
	Found - the 5th floor of Silph buiding	Price - 0
	Coin - Used to gamble at Rocket Game Corner. Trade the coins in for prizes.
	Found - Rocket Game Corner in Celadon City	Price - 1000 for 50 coins
	Coin Case - You can't gamble without it.
	Found - Diner in Celadon City	Price - 0
	Dire Hit - Used in battle, your Pokémon's attacks will be more effective.
	Found - Celadon City Department Store	Price - 650
	Dome Fossil - Take it to the Pokémon Lab on Cinnibar Island and a scientist with a strange accent^_^ will turn it into a Kabuto.
	Found - Super Nerd in Mt. Moon.	Price - 0
	Elixer - Gives 10 PP to all abilities.
	Found - On the ground	Price - 0
	Escape Rope - Use it to get out of a cave. It works exactly like Dig.
	Found - Poké Marts	Price - 550
	Exp. All - It shares experience points with the Pokémon you have that didn't fight. But since it only gives each Pokémon about 12 exp., I don't use it.
	Found - Prof. Oak's Aide on Route 15	Price - 0
	Fire Stone - Use it to make certain fire Pokémon evolve.
	Found - Celadon City Department Store	Price - 2,100
	Fossil, Dome (see Dome Fossil)
	Fossil, Helix (see Helix Fossil)
	Fresh Water - Restores 50 HP, but you can only use it during battle.
	Found - Celadon City Dept. Store Roof	Price - 200
	Full Heal - Heals all conditions such as Poison, Paralysis, and Burn.
	Found - Poké Marts	Price - 600
	Full Restore - Heals all conditions and fully restores HP.
	Found - Poké Marts	Price - 3,000
	Gold Teeth - Find them In Safari Zone, right by the Hidden House. Give them to the Game Warden and he'll give you the Strength HM.
	Found - Area 3 of the Safari Zone	Price - 0
Good Rod - Fish for Pokémon.
Found - Fuschia City	Price - 0
Great Ball - Captures Pokémon. Works better than a Poké Ball, but not as well as an Ultra Ball.
Found - One on the S.S. Anne, and buy them at most Poké Marts.	Price - 600
Guard Spec. - Use it in battle. It protects your Pokémon from elemental attacks such as fire and water.
Found - Celadon City Department Store	Price - 700
Helix Fossil - Found in Mt. Moon. If you take it to the scientist on Cinnibar Island, he'll turn it into an Omanyte.
Found - Super Nerd in Mt. Moon.	Price - 0
HM - Hidden Machine, or in the Japanese version, Hidden Manual. Use to teach your Pokémon a special ability that can also be used outside of battle. You can use Hidden Machines as many times as you want, but since these moves can't be forgotten later, you might want to use them sparingly.
Found - Depends on the HM.	Price -
HP Up - Raises the HP a little of one of your Pokémon.
Found - On the ground	Price - 0
Hyper Potion - Restores more HP than a Super Potion.
Found - Poké Marts	Price - 1,500
Ice Heal - Heals a Pokémon that is frozen.
Found - Poké Marts	Price - 250
Iron - Increases the defense of one of your Pokémon.
Found - Celadon City Department Store	Price - 9,800
Itemfinder - Helps you find items that aren't always visible.
Found - Professor Oak's Aide on Route 11	Price - 0(but you must have at least 30 Pokémon
Leaf Stone - Use it to evolve certain grass-type Pokémon.
Found - Celadon City Department Store	Price - 2,100
Lemonade - Restores more HP than Soda Pop. Buy it on the roof of Celadon Dept. Store.
Found - Celadon City Department Store Roof	Price - 350
Lift Key - Lets you use the elevator in Rocket Game Corner.
Found - Rocket Game Corner Basement	Price - 0
Master Ball - Can capture a Pokémon 100% of the time. You only get one of these, so use it wisely! I recommend saving it for Mewtwo. Get it from Giovanni, the Team Rocket boss, in the Silph building.
Found - Rescue the president of Silph Co.	Price - 0
Max Elixer - Restores all PP.
Found - On the ground	Price - 0
Max Ether - Restores all PP to one ability.
Found - On the ground	Price - 0
Max Potion - Restores HP to its max.
Found - Poké Marts	Price - 2,500
Max Repel - Will make weak Pokémon avoid you. Lasts longer than Super Repel.
Found - Poké Marts	Price - 700
Max Revive - Revives a fainted Pokémon and fully restores HP.
Found - On the ground	Price - 0
Moon Stone - Use it to evolve certain Pokémon, like Clefairy.
Found - On the ground, there are 5 Moon Stones. I know the locations of 3: 1)in Mt. Moon 2) Hidden item by the exit of Mt. Moon 3) Near the exit of Diglett's Cave	Price - 0
Nugget - Worth big bucks! If you're ever in need of some cash, sell one of these to any store clerk and you'll get 5000 Poké bucks!
Found - On the ground, also, win one by beating the Team Rocket trainers on Nugget Bridge	Price - 0
Oak's Parcel -Give it to Professor Oak and you'll get a Pokédex.
Found - Viridian City Poké Mart	Price - 0
Old Amber - Contains the DNA of Aerodactyl, an extinct Pokémon. Give it to the scientist on Cinnibar Island and he'll ressurect it for you.
Found - Secret Lab in Pewter City	Price - 0
Old Rod - Fish for water Pokémon. The only thing it can catch, though, is Magikarp.
Found - Vermillion City Fishing Guru	Price - 0
Poké Ball - Catches Pokémon.
Found - Almost any Poké Mart.	Price - 200
Pokédex - Your electronic encyclopedia. Records information on Pokémon you've seen or captured. Nicknamed Dexter.
Found - Give the parcel to Professor Oak	Price - 0
Poké Doll - Wave it at a Pokémon to distract it.
Found - Celadon City Department Store	Price - 1,000
Poké Flute - Wakes up sleeping Pokémon.
Found - Mr. Fuji in Lavender Town.	Price - 0
Rare Candy - Raises a Pokémon's level by 1.
Found - On the ground	Price - 0
Repel - Makes weak Pokémon avoid you for a while.
Found - Poké Marts	Price - 350
Revive - Revives a fainted Pokémon and restores 1/2 HP.
Found - Poké Marts	Price - 1,500
Safari Ball - Used to catch Pokémon in the Safari Zone. After your time is up, you lose any remaining Safari Balls you had.
Found - Safari Zone	Price - 500 for 30 balls and 500 steps
Secret Key - Lets you unlock Blaine's gym on Cinnibar Island.
Found - Burnt-out mansion	Price - 0
Silph Scope - Lets you see ghost Pokémon.
Found - Defeat Giovanni in Rocket Game Corner	Price - 0
Soda Pop - Restores 60 HP - more than Fresh Water.
Found - Celadon City Department Store Roof	Price - 300
S.S. Ticket - Lets you get on the S.S. Anne. If you help Bill change back into a human, he'll give it to you.
Found -	Price -
Super Potion - Restores 50 HP - more than a Potion.
Found - Poké Marts	Price - 700
Super Repel - Makes weak Pokémon avoid you. It lasts longer than Repel.
Found - Poké Marts	Price - 500
Super Rod - Lets you fish for water Pokémon. It catches more types of Pokémon.
Found - Route 12 - Fishing Guru's older brother	Price - 0
Thunderstone - Will evolve certain electric Pokémon.
Found - Celadon City Department Store	Price - 2,100
TM - Technical Machine, or in the Japanese version, Technique Manual. It teaches a special skill to one Pokémon. Unlike HMs, these can only be used once.
Found - Depends on the TM	Price - Depends
Town Map - Lets you see where you are in the scale of things.
Found - Gary's Sister, after you get the Pokédex	Price - 0
Ultra Ball - Catches Pokémon better than a Great Ball.
Found - Poké Marts	Price - 1,200
X Accuracy - Will boost the accuracy of your Pokémon. Must be used during battle.
Found - Celadon City Department Store	Price - 950
X Attack - Boosts the attack power of your Pokémon. Must be used during battle.
Found - Celadon City Department Store	Price - 500
X Defend - Boosts the defense of your Pokémon. Must be used during battle.
Found - Celadon City Department Store	Price - 550
X Special - Boosts the special abilities (i.e. elemental attacks) of your Pokémon. Must be used during battle.
Found - Celadon City Department Store	Price - 350
X Speed - Boosts your Pokémon's speed. Must be used during battle.
Found - Celadon City Department Store	Price - 350