I've come to appreciate Smashwords as a source of market data. They have a new post up today.
One of the pricing options authors and publishers can select at Smashwords is "Reader Sets the Price." The reader pays on the honor system. They can take the book for free, or they can select a price of $.99 or higher.
It's a chance for authors to eliminate price as a barrier in their never-ending campaign to reach readers.
It's worth a read.