You can easily defeat undead creatures by using healing items, such as Med Kits. Healing items can damage the following undead creatures: Lesser Karon
If you have a shop in the Ant Village and proceeded far in the game, restart with all the items you currently have and fight constantly. If you fight enough, the shop will have new skills that will be useful. It is essential to get Nina's Fire Blast and Ice Blast spells along with Ryu's Status Effect attacks. This also works well with weapons for your team.
You can steal infinite "steal items" from any regular enemy by either using the "Steal/Snatch" shield skills, or by using Lin's special combo abilites (Greetings + C'mere! or That's It! + Go on!). Once you've stolen the desired item, retreat from the battle then re-enter the battle and repeat the process as much as you like! NOTE: This trick only works where you can retreat from a battle, so boss battles won't work!
At the beginning of the game, you usually don't have enough cash to buy the items you need. Well, don't sweat it, because doing the following simple trick won't cost you a dime! Store your 5 Heal Kits and 1 Tonic in the Item Locker, and then use SOL: Restore and you'll restart with another 5 Heal Kits and 1 Tonic. Just repeat the process until your locker is completely full with Tonics and Heal Kits!
In the Frozen Road, go to the room with the 3 Jack-boxes. Lure all 3 of them in a group so that you can hit them all at once during battle. Either use D-Dash to knock them around or use meat to lure them together. In battle, transform into dragon form and use D-Breath on the trio of Jack-boxes about 7 or 8 times. Make sure you don't hold down the circle button, or else you'll kill them too early, and you don't want that! D-Breath inflicts no damage but it will count as a hit. Once you've done that, skip the rest of the first turn, it will say "zenny counter started, prize varies with HIT number". Use D-Breath again about 15-20 times and then kill all 3 Jack-boxes. They should all drop 60,000 zenny!! Pick up the money and then use SOL: Restore and repeat the process as much as you like.
For those that do not have a version 3 gameshark, these codes can be entered in and work with a version 2 gameshark:
Must be on - 0E3C7DF2 1853E59E
Infinite Party XP - DE68A72E BC413102
-Item Codes (The items will appear on page 4):
Infinite Juju - FE68A663 BCA99BA0
Infinite Reflex - FE68A66F BCA99BA1
Infinite Longfoot - FE68A66B BCA99BA2
Always have 9 backpacks - CE68A736 BCA99BB0
Max ATK - CE68A322 BCA99E6A
Infinite AP - CE68A352 BCA99BE6
NOTE: Movement will still cost AP, also AP will remain at 99 out of battle and while attacking.
Codes may cause the game to freeze after a while. Also, using sort with the item codes on may cause items to dissapear or weapons and armors to glitch (glitches may be positive or negative).