If you want to make a minimal investment to save money on your utilities, look no further than your showerhead. New low-flow showerheads use about 2.5 gallons per minute. By replacing less-efficient showerheads, you can save about $145 a year on electricity costs alone, according to the Environmental Protection Agency. This doesn't even count the amount of money you can save on your water bill. And while we're speaking of water: Always wash full loads of laundry. That one tip can save you 3,400 gallons of water per year.