PM me if you have Qs.
What stage of life are you in- single, married, kisd? making 40k 80k 120k?
Based on my gut feeling, I'm going to assume you are 22-26 years old, single, making humble salary (30-60k):
Somerville, Arlington, Medford, North Cambridge area are all pretty cheap yet not ghetto or dangerous. All of them have excellent access to the city using Orange line or Red line.
You are looking at about $700-1000pp rent with a roommate or two.
There's a saying- every Bostonians lived in Slummerville (Somerville) at least once in their life.
Stay north of Boston for those towns I've mentioned. It's cost effective, nice enough, not dangerous nor ghetto. Most residents are youngsters like you.
And they all have very trendy areas for bars, having fun, etc with all the young crowd you want (Davis Sq, Porter Sq, Harvard Sq, Cambridge itself, and of course the entire Boston).
Those towns I've mentioned, as long as you are close to a T stop (their train), you don't even need a car.
Source: I've lived in Medford, Somerville, & North Cambridge.
I miss my Boston days... I lived with a newly renovated place with 3 other roommates and paid mere $450 for rent at one point- the place was so nice... close to Davis Square for partying yet minutes away from this beautiful park & bicycle trail that spanned all the way into Arlington.