Generally only 2 materials are used to manufacture guttering in Thailand, Galvanised Steel or Stainless Steel.
Both of these are bought as flat sheets and then shaped by hand over an iron form, very few places actually have the presses.
Galvanised guttering lasts about 4 years here as most people can't be bothered clearing out leaves and other debris which creates damp patches that stay damp for long periods, I am not sure how long the stainless guttering lasts as we have only been using it for about 6 years.
The guttering is made into 2.40 meter lengths which just so happens to be the length of the sheets, and is then cut down to the lengths that are needed.
Guttering costs between 250baht to 700baht per meter length, that is the fitted price.