Who needs Amazon when you’ve got a loyal local.

Eleanor Randolph’s “The Many Lives of Michael Bloomberg” is on sale behind the bar at Union Square stalwart Old Town Bar, displayed between bottles and a “Let’s Go Mets” flag, with a handwritten sign saying “$23.00 (Price to us),” meaning at no markup.

We’re told that Randolph’s a regular at the haunt, so the owners wanted to help her on her way up the New York Times’ best-seller list.

According to publisher Simon & Schuster, the book follows Bloomberg “from modest Jewish middle class (and Eagle Scout) to … billionaire.” A book rep didn’t get back to us.