Wearing an official-looking white lab coat at her Beverly Hills headquarters-offices that she shares with plastic surgeon Randal Digby Haworth-Martens-Tomas could pass for a surgeon herself, though she might have trouble cramming all that hair under a surgical cap. And the cost of one of her services is about the same as an eyelift. Most human-hair vendors sell extensions by the “bundle,” or small cluster, to salons. A consumer who is buying a full head of extensions might, depending on the salon, spend anywhere from $800 to $5,000. And yet, on average, the process at a salon costs less than half of the initial placement with Martens-Tomas, whose clients then schedule maintenance appointments every three or four months, flying in from all over the country or paying for her to come to them.