The bus service in Menorca is great. All the buses have displays to let you know where you need to get off etc. They're clean and not crowded. I think i paid about 4 English pounds to get to Ciutadella and back, from cala n Forcat. It took about 25-35 mins and was an easy route to remember. There are bus stops clearly marked through the main road in cala n Forcat. You pay on the bus for a ticket, but at Ciutadella you pay at the booth before you get back on the bus. The drivers we had spoke good English too, so if you weren't sure where you needed to get off they would let you know.