I'm about to start designing an inventory system, and I have NEVER done anything like this before. I suggest you read up on tutorials, search the forums for other users who have done it, etc. Also search Google for other code besides C2 that someone has made, and see how they do it, as well. It's as hard as programming anything else (which isn't hard at all) but I do think an inventory system requires a little more planning than most other things.