The US Post Office is taking another shot at ending first class mail delivery on Saturdays. The goal is to save $2 billion — after losing $15 billion last year. At a news conference this morning, Postmaster General Patrick Donahoe attributed the loss to a steady decline in first class mail, as people increasingly pay their bills online. He conceded, "It's easy and it's free. You cannot beat free." Ed O'Keefe is congressional reporter for the Washington Post, where he contributes to the Federal Eye blog.