Admission fees? Retail stores are increasingly losing to online services, so the brick-and-mortars might have to focus on the experience of being in a bookstore.

For more on this idea, The Experience Economy is a good read. (Skip everything but the first 2-3 chapters. After that, it gets redundant and a little weird at the end.)

http://www.amazon.com/Experience-Economy-Theater-Every-Busin...