First of all, this place is HUGE. The used book section takes up most of the space, but McKays also has a large movie and music section as well. The prices are good and you're sure to find at least one thing each time you go in.
It's not usually a good idea to go in with the intent on finding a specific item. There's a good chance you won't find it. It's better to go in and browse the titles until you find something that catches your eye.