There are frequent buses from Podgorica that cost â¬6, a 2 hour ride.
From Bar you can either take a normal bus or catch a 'combi' minibus that runs up and down the coast of Montenegro. The ride from Bar takes about half an hour.
From Kosovo during the tourist season there are frequent buses leaving from the major cities. The price should be around â¬25. Buses leave at 7pm each day from both Pristina and Ulcinj and are 11 hours each way, making about 4 rest stops on the way.
From Albania there are 'combi' minibuses that come from Durres in Albania to Ulcinj, although they most likely are not official bus operations, so you'll have to do some asking around.
There are also daily departures from Shkodra in Albania to Ulcinj 6 am and 12:30 pm. These are, in theory, well connected with Albanian 'furgons' from Tirana and Durres. It takes 1 hour to Shkoder by "private" cab.
