8. Black Printer Ink ($720 per liter)
Printer manufactures sell their printers at a low price, and earn back their money and then they charge a lot for the ink cartridges. Black ink, in particular, is costlier than the other colors. Additionally, the high price of ink is justified by the billions of dollars that companies spend each year on ‘Ink Research and Development’.
7. Mercury ($900 per liter)
Mercury is a liquid metal which was traditionally used in medicine and the production of thermometers. It can be used to conduct electricity, and in vapor form it is used in street lighting and fluorescent bulbs. The extraction and processing of mercury from the Earth’s crust is a very difficult and costly job.