Is printer ink the most expensive liquid in the world? Well, we can't say for sure, but it sure feels like it when it comes time to buy a new cartridge. Per-gallon, printer ink costs considerably more than milk, vodka and even gasoline. This infographic compares some common household items against the cost of printer ink. As if that isn't shocking enough, according to Consumer Reports, many printers waste as much as half the cartridge. Find out more in the infographic below. And here's hoping for a paperless world.