There are two types of stove pipe that are commonly used; galvanized and black. Both have their own benefits and drawbacks that should be considered before choosing which one to use.
Galvanized pipe is made of steel that has been coated in zinc. This gives it a shiny appearance and makes it more resistant to rusting than regular steel. However, the zinc coating can eventually wear away, exposing the underlying steel to corrosion. Galvanized pipe is also more expensive than black pipe.
Black pipe is made of plain steel with no coating. It is cheaper than galvanized pipe but will rust more easily. Black pipe is also more likely to cause soot build-up on your stove or in your chimney since it doesn't have a protective coating.