This is the most common method and cheapest. as you can see there are different styles and uses. But generally there are Two, Metal and Glass and Glass is preferred. not only does metal heat up quicker which can burn you, but glass is nicer looking and healthier for you especially in the case of aluminum, never attempt to make your own out of a Soda Can or other of this sort as it is known to cause severe health problems later on in life.
Acquired from a Grower Friend, Corroded by Alcohol and other Cleaning Substances not recommended… but only The Part that The Crocodile sits on.