[cyberbanjo]

Availability? Helium at any party store, but I thought you needed to do something illegal or jump through hoops to get laughing gas

[globular-toast]

Laughing gas is nitrous oxide (N2O). I'm talking about normal atmospheric Nitrogen (N2). Nitrogen is available anywhere and significantly cheaper than Helium. Nitrogen can be used for welding or for brewing certain types of beer.