I am not answering your post directly as I also, don't know anything about scripting.
It occurs to me that if the users are printing lots of pages then they need them? Or do they?
How many users are there? What are they actually printing? Is it essential that they have hard copies?
There are lots of variables here. Compatible Ink Cartridges for this printer can be bought for almost half the price of originals from click here
Can you not make a charge per user to help alleviate the ink charge?