For argon the answer must be yes. The atmosphere is about 0.7% argon (which is quite a bit if you think about it) by volume, meaning you can distill this gas right out of the air. The cost definitely makes sense here.
Graham's law explains the relation between molar masses on the rate of diffusion. It should be the the inverse square root of the molar masses if I remember correctly, meaning Helium diffuses roughly 3.2 times as fast as argon (turns out that it has around 40 daltons of mass).
However, I need...
I have a question about helium :
If it is the most inert substance, why isn't it used more than krypton or argon for high-temperature incandescent bulbs?
I don't see neon in light bulbs too often either.
Just what, exactly, is its melting point?
I came across a ICSC website saying it decomposes at 350 degrees Celsius. Now how is that supposed to make sense, when it is itself a by-product of wood fires?