Some economists describe a "free good" as something that is so common, it's practically free. Most of us would hardly think twice about taking a paper clip home from work, or a staple, because there are just so many, their value is hard to even quantify. A box of 25,000 staples might cost $5, so an individual staple costs less than 1/1000 of a cent. Practically speaking, you couldn't pay your employer for that staple if you wanted to! Sometimes it seems like such is also the case with time...