Helium is actually a precious resource, and it's estimated that we'll run out of it in the next 25 years.

 You probably know it as the gas you put in kids balloons, but Helium is actually a non-renewable gas and that we continue to squander on silly things like making our voices sound funny. That birthday balloon should probably cost more like $100 because aside from birthday novelties, Helium also has some more serious uses, like cooling nuclear reactors and cooling the magnets in MRI machines, and once it's gone...it's gone. The US stores 80% of the worlds helium, and because they refuse to treat helium as a precious resource scientists estimate that our Helium supplies will be exhausted within 25 years.
http://www.dailymail.co.uk/sciencetech/article-1305386/Earths-helium-reserves-run-25-years.html