Material Cheat:

Cheat submitted by Max Tatton-Brown

First get the W-Item Material. Then equip it and start using it.  Select the item, use it, then when it asks you for another item click on the same item.  The arrow should hover above one of your characters.  Now press cancel and the item will reappear.  Keep pressing Enter then Cancel and you should eventually get 99.  

This is especially good with sylkis greens and megalikers.