With this you can sell the shop it's own items.
1. Go to any shop.
2. Grab any item of your own.
3. Press R three times.
4. Take it back to your inventory.
5. Drop it.
6. Go over to any item that is for sale and you can purchase.
7. Grab it.
8. Drag it in your inventory.
9. Press R.
10. Drop it.
Note: You Must Be Able To Purchase The Item
1. Play in multi-player mode (works best with 2 players).
2. Have player 2 drop items desired to be duplicated.
3. Player 1 then picks up the items.
4. (Timing Essential!) Player 1 goes to start menu and selects end game. Player 2 gets ready to turn off GBA and does so as soon as player 1's screen says game saved.
5. Enjoy having both player 1 and 2 having possession of the items.
At the name entry screen, enter one of these names for bonus item(s) in the inventory at the start of the game.
Naming the characters as a certain Shining Force character nets a bonus in stats when you start the game.
Warrior - Max - +10 Str
Archer - Hans - +10 Vit
Mage - Anri - +10 Int
DragonNewt - Bleu - +10 Dex
During advanced mode make your way to the Dark Castle. On the map press and hold the L and R buttons while selecting the level. This should bring you to a secret dungeon.