Bottled water
The price of bottled water is, on average a 300 percent markup over tap water, Slate reported, but the markup is more like 2,000 percent when bought in individual portions. (These numbers are from a few years ago, and the way people calculate the markup varies, though they reach the same conclusion — bottle water is crazy overpriced.) Saving is simple: drink tap water. In most of the U.S., tap water is perfectly potable. If you’re concerned about taste or quality, use a water filtration system.