For a very limited time, Jon Eller's literary biography of Ray Bradbury - Becoming Ray Bradbury - is being offered in a special promotion from the publisher, Illinois University Press. In case you don't know, the book is a fascinating study of Bradbury's early writing career, and reveals the influences on Bradbury's developing authorship during the period when he was at his most creative and most prolific.
If you are an e-book user, you can get the full e-book version for a ridiculously cheap price of $2.99. Versions are available for Kindle, Nook and Kobo. The offer is good until the end of June. I don't know whether the offer is geographically limited.