Heal Up weapons:
In Morune village at the begining of the game, in the dungeon you chould get a new 
sword or slingshot. If you use one of them and Gaffers buggy is not open and don't 
have more than 1 repair powder, then you can do this cheat. 1st go to the mayor house. 
Go in and use your repair powder. Now talk to the mayor and he'll give supplies. Do 
this as much as you want until your weapons are all healed up.

Weapon Level-Up:
If you're into upgrading your weapons and creating Synth Spheres, here's a helpful tip 
that lets you quickly raise low-level weapons to Level 5 so that you can Limit Break 
them in a sphere. The problem is of course that fighting tougher enemies with a low-level 
weapon not only requires you to repair it frequently, but it also takes a long time to 
defeat the enemy. But why fight with the lower level weapon? Simply pick your most powerful 
weapon, and quickly defeat the enemy. Now, before the slain enemy vanishes, switch to the 
weapon you want to upgrade. Since there is a small delay before the WHP for the defeated 
enemy is added, you can easily build up lesser weapons that aren't suited for the enemies 
you're fighting -- so that you can turn them into spheres and add their powers to your 
favorite weapon.

Easy Free Items:
Before finishing Gaffer's Buggey in Norune village, win the duel with Master Jacket 
(the skeleton with the jacket) in Divine Beast Cave. Every time you go through that floor, 
there will be no enemies, and the Mayor gives you items every time you go through a cave, if 
Gaffer's Buggey is finished.