Where do you find bellcastay paper?

There seems to be a misunderstanding. There is no known paper type or brand called "bellcastay". It's possible you've misspelled the name, or it could be a very obscure or niche product.

Could you please clarify:

* What kind of paper are you looking for? (e.g., art paper, writing paper, construction paper)

* What is the purpose of this paper? (e.g., for drawing, writing, crafts)

* Did you see this paper name somewhere? If so, please provide the source (e.g., a website, a store, a book).

With more information, I might be able to help you find what you're looking for.