Book fair flyers were the best thing in the world. Hundreds of books for you to go through and put a little check box next to that meant, "Buy me that one, mom." Parents couldn't say no to a book fair request because it was for books after all. It's not like you were asking them for a toy or a violent video game. A book was worth the investment. The cool thing was that the book fair flyers would also have VHS and toys. You could try to sneak one in if you were lucky.
Now there's no reason not to do this type of flyer online, though sometimes paper is better. The paper might hold less information, but that's what was nice about it. It was mysterious yet informational all at the same time.