Argon is the third elements of the Noble Gases with chemical symbol Ar and atomic number 18 (Noble gases family consists of He, Ne, Ar, Kr, Xe, Rn; Rn is not for sale because is highly radioactive and very dangerous for health, the others are not radioactive and safe). Argon is a colorless gas but when it is rarefied (low pressure ampoules) it can be lighted up with an high voltage transformers or a better way is to use a simple tesla bulb (the toy kid). Our Air consists to 1% of argon, which makes it an abundant element in our direct vicinity. Therefore it is the cheapest and most frequently used noble gas, which comes into operation when an inert atmosphere is needed, like our ampoules argon sealed (Cs, Rb, etc...).
High purity Argon gas element 18 sample in mini ampoule inside glass vial, it is a low pressure sample (rarefied) which can be lighted up with a simple Tesla Bulb (kid toy), not on sale here. Very pure Argon gas sample. You can find this amazing ampoule only here. Pictures shows real image of the sample.