Helium balloons.
The International Balloon Association knows it falls toward the end of the line behind hospitals when it comes to filling up helium tanks, but thanks to the shortage in helium — and higher demand from high-tech industries — party stores are paying triple the price of a few years ago, and sometimes going weeks at a time without refills. Interestingly, the very thing that makes party balloons float is what makes helium storage problematic: as one of the lightest gases in existence, helium simply floats out of Earth’s atmosphere and into space — meaning that as with fossil fuels, we’ll eventually run out of the gas entirely.