Guild of Tokens by Jon Auerbach

The quests are real, the rewards are real, and the dangers are unimaginable. All Jen Jacobs has achieved in life is loneliness. So when she stumbles across a real-life game of epic quests on the streets of New York, she jumps at the chance for some excitement and gold tokens. Little does she know that the items she strives to collect hold a darker purpose… After a particularly harrowing quest pairs her up with Beatrice Taylor, a no-nonsense and ambitious mentor, Jen hopes she’s on the path to becoming a big-time player. But as she dives deeper into the game’s hidden agenda, she realizes Beatrice has her sights set on the Guild, the centuries-old organization that runs the Questing game. And the quests Jen loves are about to put both of them in grave danger. Will Jen survive the game before powerful forces cut her real life short?