Essaouira isn’t that big. The medina is completely navigable on foot (and pedestrianised). As a tourist, it’s unlikely you’ll need to be in the newer areas outside the medina walls very much. There is a group of cafes, restaurants and activity centres (kite surfing, camels, horses, quads etc) at the far end of the beach. It’s about a 30 min stroll along the promenade or the beach to get to them from the medina. Otherwise, taxis are 6.5dhs per journey (not per person) during the day and 8dhs at night. You can flag them down outside the medina or pick them up at taxi stands at the four main gates in the medina walls.