yeah, it was very easy to make insane amounts of money very quickly with the zknife, though i guess if you want to still use the knife, get a cramp card to help boost some chance of getting zeny. maybe two cards.
though i think wizards would still do fairly well if they went down to a mobby area with a zknife, even though it's a % chance and only 100z no matter the monster? if you need to be near the same level as the monster in order for it to work, then that sucks too. hope not though.