书店

Chinese uses 家 as the counting word for stores, restaurants, and hotels. It treats them like businesses or homes. 个 is fine for many objects, but shops usually take 家. Say 一家书店 when you mean one bookstore. Use 这家书店 or 那家书店 when pointing to a specific one.

有 means a place contains or has something. 是 links two things and says one equals the other. A bookstore is not a book, so 书店是书 is odd. You say 书店有很多书 for what it has. Use 是 for identity: 这是书店 means this is a bookstore. “书店有好书， 饭店吃和住， 酒店没有酒。” (A bookstore has good books; a restaurant offers food and lodging; a hotel doesn't have wine.) ── [《三星在哪里？》](/read/where-is-samsung#s5)

Chinese often drops 一个 when you talk about a general destination. 去书店 means you are going to a bookstore, any bookstore. Add 一个 when the number matters or you are telling a story. If you mean a particular one, 我想去一个书店买书 can work. For daily plans, 去书店 is the normal choice.