In FINAL FANTASY VII there is a nice glitch, otherwise known or called as a cheat. With it you can duplicate your items over and over again.You will need the X-Item Materia and atleast two of the item you wish to clone. Only items that are able to be used within the "Item" command in battle may be duplicated.

If you don't have the X-Item Materia, don't get upset, I'll tell you how to find it. After the weapons have been released and you return to Midgar, go through all the passageways and tunnels until you meet Reno, Rude, and Elena. It doesn't matter if you choose to fight them or not, what matters is when the conversation is over, that you go towards the camera instead of going forward. It will be a long way to go, but after a long walk through many screens and annoying random battles you will find a yellow Materia lying on the ground. That Materia will be non-other then the X-Item Materia, congratulations on finding it.

Equip the Materia to one of your active characters in your party and then in battle, when their turn comes up, select the X-Item command and chose an item to use on a character. You can then choose another item, so select it, but do not use it. Instead press the cancel button, and select the item again. You will see the number of the item increse. Continue selecting and canceling the item until you have the amount you want. If you duplicate the expensive greens, then you can sell them all for alot of Gil.