I heard once that Gillette made his money by selling razors cheap, but charging a lot for the blades. I think that is the same for printer companies. I understand that and I still fall into their scheme, for I have to print things out. Recently, we bought a Kodak printer because they said their printer would be better usage of ink than the others. Wrong! As far as I can see, that is.
I put in a new cartridge and kept track of the prints I made (knowing I was going to make a lot at that moment). It basically printed about what they said considering I had lots of photos in the batch. However, I printed it all in black and white and still watched the graph for the color cartridge go down with each printing. It was heart-breaking because, though I knew I'd use the whole black cartridge, I thought the color would stay there being I formatted the whole document in B&W and told it to print in B&W.
An interestng article. I tried to find more, but could not.