EarthBound/Tips and Tricks

Infinite Items
The most useful trick in the game involves any single-use item and a full inventory of condiments. You should have in your inventory the item you want to be able to keep using and condiments that are compatible with it. Go into the item screen and select the item. Give it to yourself so that it is at the bottom of your inventory now. If it is a healing item, enter battle and you can use it as much as you want, until the condiments runs out! The item will never go away.

The best way to use this trick is to fill up your inventory with Sugar Packets and a single Rock Candy. Give yourself the Rock Candy so that it is at the bottom of your inventory. Now use it on your character until the Sugar Packets run out to increase your stats indefinitely (you must do it in a battle or else it won't work). Buy more Sugar Packets when you run out and continue. Using this trick, you can completely max out everybodies stats. Be careful though because if your stat goes over 255, it will reset to 0 causing your characters to be very weak.

Infinite Magic Butterflies
When you find a room with a butterfly fluttering around inside of it, you can continuously re-enter to keep regaining PP. Use this trick to gain some levels by fighting until you are out of PP, and then restoring it. You can use up your PP healing your characters and then restore it and continue to fight. This is most useful in tough areas directly before Your Sanctuary bosses.

Easy Experience
To get a lot of experience quickly, find a Criminal Caterpillar in Dusty Dunes Desert or the Master Criminal Worm in Scaraba and chase it down. It is an easy enemy that gives you massive experience when defeated. The Criminal Caterpillar gives over 30,000 experience which is 10 times as much as other enemies in the area. The Master Criminal Worm gives over 80,000 experience, which is the most experience you'll get in the game from a single enemy.

Money

 * To get money quickly, buy a bunch of Fresh Eggs. Wait around until they grow into Chickens and then sell them off for a $98 profit.  You can also fill your inventory with Fresh Eggs from the Monkey in Monkey Caves.  Just exit the room and re-enter to get another Fresh Egg to add to your inventory (you may have to wait until each egg turns into a chick before getting a new one).  Sell these Chickens off for even more money than if you bought the egg!
 * Stock up on Broken Spray Cans after Jeff joins your party. Stay over night at an inn and have him fix the Spray Cans creating Defense Sprays (he can only fix one item a night, so you'll have to stay multiple times).  Sell these for a $61 profit.  For best effect, rest at places that are free.
 * If you get mushroomized, sell your mushroom to the man at the hospital for $50!
 * There is a man in the Twoson hotel lobby that if you talk to him over and over again, he'll eventually give you $50. You can only do this once.

Item

 * Jeff's Spy command can steal items that the enemy may have, as well as tell its weakness. Very useful when hunting for those 1/128 items and you don't want to have to defeat the enemy.  Note that if you don't get an item by spying the first time, the enemy does not have one on it at all.
 * Before Buzz Buzz joins you, make sure you have a full inventory of Cookies won from Spiteful Crows in the area. Buzz Buzz will give the Soundstone to Tracy instead which means you don't have to carry it for the rest of the game.  Be careful that you don't talk to Tracy or she'll force you to take it.
 * There is an Insignificant Item in a drawer in Threed Hospital. Take it to the man in Twoson's Hospital and you'll be given a Magic Truffle!
 * To make Mach Pizza deliver faster (they are usually very slow) call them and save your game. Reset and load up the game again and the Pizza will be delivered immediately.
 * If you're carrying a lot of food or other healing items, and you're about to head out into a dangerous area, consider calling Mach Pizza before you go. By the time it arrives, you'll have enough room, and until later in the game a large pizza will usually heal your party to full.

Battle

 * If you are low on health and you don't want to fight any more enemies, backtrack until the enemy is off the screen. When you come back, it will most likely be gone or replaced by a different set of enemies.  Repeat until you're ready to move on.
 * If you are fighting multiple enemies and want to run away, defeat a few first and then try. You are more likely to be successful in fleeing from battle if there are less enemies to run from.  Unfortunately you will not gain any experience for enemies you kill if you run.
 * You can go through Lilliput Steps without worrying about any enemies if you head back to Twoson and talk to the Runaway Five. Don't go to Threed with them when they offer and instead head back to Lilliput Steps.  You'll notice that there are no monsters anywhere (including Twoson, Peaceful Rest Valley, and Lilliput).
 * If you take items from the shop in Happy Happy Village without paying, a man will notice you. Talk to him and he'll fight you!
 * When Poo gets a status effect, use Mirror and he'll be cured of it.
 * If you have a Teddy Bear that is getting low on HP, call Escargo Express and have them pick it up. Get it back from them and it'll have full HP again.

Miscellaneous

 * When in Moonside, you can talk to the Mani Mani statue without talking to Monotoli first. Just check the statue from a distance.
 * Try teleporting while underwater in Deep Darkness. You will teleport with the periscope on top of your head!
 * You can use the teleport to move faster when in slow moving areas (such as Deep Darkness). Just be sure you don't move too far or you'll teleport away!
 * The teleport can be used to bypass some photograph locations if you do not wish to have your picture taken.