Some uses for argon gas are for what are called "neon" lights, for a shield gas during welding and as an insulation between energy-efficient window panes. Argon gas is also used with nitrogen in light bulbs to save the filaments from oxidation.
Argon is a noble gas which under normal circumstances doesn't react with any other element. This is why it's used as a shield gas during welding. Its use protects the metal that's being worked on from the oxygen in the air.
When argon is excited by a current of electricity, it glows with a bright blue light. This makes it sought after for light signs and indicator lights.
Crystals of germanium and silicon are grown in protective atmospheres of argon. Argon is also used to humanely slaughter chickens and even helps prolong the time when the meat is good to eat. It's used as a food preservative overall.
Argon is also used to fill the "dry" type of scuba diving suits.
Though other inert gases can fulfill the functions of argon, argon is especially attractive because it's inexpensive and plentiful. It makes up nearly one percent of the atmosphere and can be obtained through the production of liquid oxygen and liquid nitrogen.