Everything has value. Or rather, everything has the potential to hold value (or Utility, if you want the proper term) for someone.
Not every value can be easily translated into currency, however. Putting a monetary value on human life, for instance, is controversial. Luckily, we are not talking about these. We are talking about everything else, from physical goods, like the chair you are sitting on, to virtual ones.
For instance, how much would you pay for an Achievement?"