Well it sort of depends on you knowlegde of the trigger system. If you haven't used virtual health, death counters, and things like that then you probably won't have much luck because it can be a long and complicated process.
I would need to know:
1) What systems you already have in place in terms of battles in general, virtual hp, etc. (You can have an item system without any other stuff (VHP and the like), but it would be rather crude. )
2) How much time you are willing to spend.
3) Your unit, space, and location budget.
If you could tell us these three things, it wouldn't be too hard to find an item system that fits your needs.
Hey wing I am just starting to learn this advanced stuff. I already know what VHP is but i still dont know how to use this "inventory system". By the way, Corbo that gave me a vague idea of what it is. Thanks.