Creating Stackable Items?

[Cubical]

What would be the best way to create stackable items while still having different ID numbers on the items? I can't seem to figure out a way to do this, any ideas? Should I stack by name? I'm not really worried so much about weapons but things like lets say arrows, bullets, or whatever else that is stackable that you can't just put 1 in each inventory slot. I'm sure there is a way to do it, I'm just clueless on how. I haven't started scripting anything yet because I wanted to get all the details first so I don't get stuck half way through and have to start over. I'm currently just making something simple with no real purpose to learn from and expand on until I feel comfortable enough to do something for real. Any ideas on what the most efficient way would be to solve this?

Edit: Corrected some of my wording.