The ergonomic principles to the design processes, workplace and organization, has to be applied not only to respond to legal requirements, but also for answer to the companies' needs for pursuing a business logic. This paper shows a cheap and effective method to acquire workplaces, work-cycles and workers-postures, in a supermarket, in order to analyze how cashiers move them-selves into their workspace, with their own tools and devices and do their jobs. Photo and video acquisition has been done to acquire postures and movements by DARTFISH® software; DELMIA® software was used to model humans postures, workstation and interactions. Simulation results were processed by CaMAN® software for evaluating comfort indexes both for each task and globally. Lastly, results have been correlated to subjective perceptions through experimental tests, in order to validate the comfort model