Gredery shop + collab questions!

So I haven't experienced gredery shop or collabs before, but I have seem in the catalog the items from previous years and I ABSOLUTE LOOOVE IT!

My question is, when usually do gredery/collabs happens and what are the prices for the items (N, R and SR)?

I heard someone saying that the collabs are usually like the mahara banners we have, and you just pull for items, is it true?

this year will be my first year experiencing both, I would love suggestions and advices 🤍🙏🏼

thank youuu in advance 🤍🙇‍♂️