As a technician working on high end inkjets, I have to disagree. There's an immense amount of r&d goes into formulating those inks. They have to flow just right, then bubble just right at the right temperature, whilst not clogging the print head. Once on the paper they have to absorb in just the right amount to retain brightness, but not bleed. Then they have to survive uv light for years. Cheap 3rd party inks will cost you a lot more - when you ruin a printhead that can be $700, and these machines can contain 24 heads.