At San Francisco’s Lost Art, the experience of buying art is deliberately “anti-gallery”: unintimidating and — gasp — affordable. “There are no pristine white walls or fancy track lighting. Instead, framed paintings by unknown artists and others on the cusp of stardom occupy nearly every inch of available wall space in the cozy salon, which is dolled up with midcentury furnishings to feel more like some cool bohemian aunt’s living room than a place of business.”