Which beach are you planning to go to that a taxi would be inexpensive from Dedham? And what is your plan to get a taxi from this beach back to Dedham?

Nothing wrong with staying in the 'burbs rather than paying Boston prices, but what is your big picture?

Visiting downtown? Just going to a beach? Are you doing ANYTHING around Dedham? (visiting family or friends)?

I see there is a bus that goes from Dedham to downtown...but have you checked on its hours? Is it just a commuter bus? (good service in the morning and back in the evening?)...what is its schedule based on what YOU want to do? (Nightlife in Boston? Kids with you that need to nap during the day? You like to freshen up before going out to dinner in Boston?)

Don't be lured by a false economy.