The customer, along with three others, had ordered four coffees, each priced at €2 each, as well as a croissant, priced at €2.30 at the Calise bar, located in one of the most touristy areas of the volcanic island off the coast of Naples.
However, the group failed to take into account that they would be charged an extra €5 a head for service.
Outraged, the customer took to Facebook to express their anger at the bill. Within a few minutes the receipt had been shared widely on both Facebook and Twitter, according to Il Messaggero.
Staff at the bar were unapologetic and explained that the service charge was fixed for the first drink ordered.
Despite the four-star rating on the traveller review website TripAdvisor, bar Calise has also attracted several other complaints about its prices.
This is by no means the first time Italian bars and restaurants have hit the headlines for ripping off tourists. In the summer of 2013, a group of British tourists in Rome who were charged €64 for four ice creams gained international headlines.
The Italian authorities were so embarrassed by the negative publicity that they invited the tourists back to the city to experience the best of Italian hospitality.
The following summer, an American couple who were charged €42 for three ice creams and a bottle of water at a bar in central Rome even asked police to intervene. On that occasion the manager of the bar told The Local it was "their fault" for not reading the menu.