As we edge closer to a cashless society, some consumers are quietly challenging the idea of money in the first place––by giving it up completely. Daniel Suelo, 50, traded his nine-to-five for dumpster diving and a cozy cave in Utah's canyonlands back in 2000. But even before Suelo, there was Germany native Heidemarie Schwermer. In her early 50s, Schwermer decided to see what it'd be like to leave her cushy job as a psychotherapist and live money-free, a journey that's been documented in the film "Living Without Money." Sixteen years later, she hasn't looked back. Schwermer, now pushing 70, recently...