The original editions of the early Bachman books are among the most sought after original paperbacks in existence, costing at least a couple of thousand dollars.
By the time of Bachman's death (supposedly from "cancer of the pseudonym"), King was working on Misery and planned to release it as a Bachman book.
In the mid-1990s, The Regulators came out, claiming to have been found among Bachman's leftover papers by his widow, but it is obvious from the book that it's really by Stephen King (there's a picture on the back flap of a young Stephen King). King has said that there may be another Bachman novel left to be "found".
After the Columbine High School massacre, King announced that he was going to allow Rage to go out of print, fearing that it may inspire similar tragedies.