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Pure liquid helium is used for cooling the superconducting magnets in medical scanners and the like.
Despite thermal insulation it continually boils of, and some of this is captured and sold as "balloon gas" which therefore contains a variable proportion of air.
Supplies of helium are limited as it forms very slowly due to natural radioactive decay deep underground, it comes to the surface mixed with natural gas from which it is extracted and sold.
Argon by contrast is relatively common, air contains nearly 1% argon. vast quantities of air are liquified to produce liquid oxygen for medical purposes and industry, and liquid nitrogen for cooling. Argon is thus produced.

If you want argon, have a look on-line, several suppliers offer it cheaply, for example by including free cylinder hire subject to purchasing one refill a year.