I am using Helium gas to inflate a balloon. Which can do you use to inflate a balloon?
Helium and hydrogen are the two gasses people use for HABs. Helium is slightly more common but many on this forum use hydrogen because it is lighter and cheaper.
We mostly use balloon gas for our flights. Balloon gas consists of 96% helium and 4% oxygen. Balloon gas is much cheaper than helium in Europe. The difference is not noticeable in the result.