We were asked more than once how to get in Montenegro from point A to point B cheaper. If you do not want to spend money on taxis, car rentals and transfers, then you should remember about the good old buses and bus stations. Each "large" city of Montenegro has its own bus station, from where you can go to any city in Montenegro, as well as to neighboring countries, for example, to Belgrade and other Serbian cities, Dubrovnik and other cities of Croatia, Bosnia and Herzegovina, Macedonia, etc. Bus stations in Kotor and Podgorica even have their own website with contact numbers, addresses and flight schedules. Tickets, unfortunately, cannot be bought through the site, you will have to go to the station in person. Just in case, I give the telephone numbers of the stations in Budva, Bar and Sutomore - although they are unlikely to answer you in English there, you need to know at least a little Serbian.
Bus station in Podgorica www.busterminal.me
Bus station in Kotor www.autobuskastanicakotor.me
Bus station in Budva +382 33456 000
Bus station in Bar +382 30 346 141
Bus station in Sutomore +382 30 373 308
Bus station in Ulcinj +382 85 413 225
Bus station in Herceg Novi +382 88 321 225
In general, there is such a summary site with the schedule of all bus stations in Montenegro http://www.autobusni-kolodvor.com/en/terminal.aspx?d=499 This site also provides bus timetables for Croatia, Serbia and Bosnia and Herzegovina.