If you're just visiting, a quick and cheap way to get around Boston is the MBTA-Boston public transportation system. Nicknamed "T" by locals, it includes the metro, bus, trolley, water taxi / ferris. The "T" can take you anywhere in and beyond the Greater Boston area.
Certain ways to get around are rental cars, taxis, the city's bike-share program called the Hubway, city tour trolleys, and walking (the community is small enough and called America's Walking City). If you're looking for a way to see Boston Attractions, the Go Boston Card is a cost-effective way to get around.
infographic by: www.way.com