Hi,
Depends what type of ark you are looking for and what the budget is.
You will get advice ranging from making one out of straw bales to various other arks.
Ask yourself some questions first - How many Pigs? Breeding or just fattening? wood / plastic or metal? and how long do you want it to last?
We sell arks, but mainly aimed at commercial producers as they will last 10 or so years if looked after.
Thanks