Dry ice is very cold and is made from carbon dioxide, so it can be used in a variety of ways. It's extremely cold and melts quickly to form a thick, white powder that then becomes a cold gas that you can use for many different things.
You may think that it's cheaper to buy dry ice from a store than to make it yourself. But you can also make it by using a fire extinguisher or putting pressurized carbon dioxide in a tank.
Put the nozzle for the fire extinguisher or CO2 canister in a dry ice bag. You need to place the nozzle on the fire extinguisher and the CO2 canister in the bag, and then close the valve. Keep the bag in the freezer and keep it covered with freezer bags.