The settlement would reimburse consumers in 33 states whose authorities sought damages for Apple's price-fixing, according to a statement from New York's attorney general.
But the settlement is contingent on the verdict being upheld in a July 2013 federal court ruling that Apple violated antitrust laws by orchestrating a conspiracy with five publishers to raise e-book prices.
If Apple's federal conviction is overturned, no money will be paid. If the case is retried, the settlement amount will be $50 million, the statement said.
Apple will also make payments to the 33 states of $20 million to cover costs, fees, and civil penalties if its conviction is upheld.
"This settlement proves that even the biggest, most powerful companies in the world must play by the same rules as everyone else," said New York state Attorney General Eric Schneiderman.
Apple's deal with the publishers as it introduced its iPad tablet shook up the existing model, but US officials said this was an illegal conspiracy which raised prices.
Copyright Agence France-Presse, 2014