My game project originated in RPG Maker 2003 but recently I found my legal license for XP so I decided to port it over there. The Big thing I wanted was a Forging system to make all types of Items and such. Of course 2k3 has no scripting so I made an event based system that was easy to do.
In a nutshell, Make a big show choices Common event that sets tons of variables for every Item you want to use in the forge.
Optionally you can make Switches to activate only certain Sections of the Forge and put it on a Item or a book.

Ok let's Get started, keep in mind I am generalizing and you can easily adjust where you need it.

Here our Items in our example:

1. 0001 Copper
2. 0002 Iron
3. 0003 Root
4. 0004Water

First Put a Label down (Label 1)
This is the time to set variables to count your possesed item:
Variable[0001]=Copper in inventory ect
after you account for all items put label 2 down for the actual forge
You can divide the forge items using choices here is an example
Weapons
Armor
Accesory
Medicine
If you have more than 4 choices put your 4th choice as "More..." to continue on.
If you choose not to make categories that is fine.
Lets say we have 4 items to make
Show choices:
Sword
Plate Mail
Ring
Heal
under each already decide what will make each item
for example: Sword needs 2 copper and 1 iron.
Check the items possesed using conditiona branches as follows
If "Copper Variable" is less than 2
Message:Not enuff
<>Else
If "Iron Variable" is less than 1
Message not enough
<>Else
Remove item copper 2
remove item iron 1
add item sword 1
Message: Got a sword!
Goto 1

Why goto 1? Because everytime you use an item, you need to update all your variables.

repeat this for every item and you will make a stable forge


On the switch part just put conditional branches
Lets say we have these choices
Lvl 1 sword
Lv 2 Sword
you dont want lvl 2 sword to show its items unless you read the book for it
so when you select the Lvl 2 sword choice put a conditional branch that if the switch is not on go back to the last menu
here is an example:
[Lvl 2 sword handler]:
Branch if 2swordswitch is Off
Message: Can't make this
Goto: 2 (don't need to update items)
<>Else
((Make sword))

Got the jist right? No? I prepared an Example for you with 8 Items.
Here we go.


If a Demo is needed I will make one later.