The only difference is the order and both are perfectly fine. First sentence means At the bookstore I bought this book and the second one means I bought this book at the bookstore.

Both right! Also please put a period at the end of a sentence. It'll look more natural. ex) 저는 서점에서 이 책을 샀어요. 저는 이 책을 서점에서 샀어요.

Both, really.

둘은 정확해요. 잘 쓰시네요 ^^

hi