I lived in/near Boston from 2000-2003. In the less desirable places I lived outside the 95 loop my rent was in the $1,500/month range. Inside the loop (barely), but still not in Boston proper, rents were $2k(ish) for a decent apartment. Things may have changed since then, but it's not common for rents to go down over time.
If you don't mind living with roommates, you can have a decent standard of living. With a take-home pay of a bit more than $40k/yr, it would be tough to chew on losing half of that to rent if you try to live alone. I was working with my Masters at the time, so my take-home was quite a bit better, but I still cringed at how much left my pocket every month. In some areas, Boston is approaching New York in monthly cost.
Parking is also a bear... make sure whatever place you get has reserved parking, especially the closer you get to the city. The last thing you want to do is circle the block 20 times waiting for a spot to open when you just worked a 10 hour day and have groceries in the car. Parking spots in the city can be $500-1k/month. Think metro travel will save cash? Sure, as long as you don't need to get anywhere in a hurry, and ever try to carry a lot of groceries on the metro? Better make sure you live within walking distance of a station and don't mind walking to it when it's below zero outside. Driving yourself? Prepare to sit in a parking lot (the state calls it I-95) anywhere within 2 hours +/- of rush hour. For one job, I lived 11 miles away (Marlborough to Maynard)... took me an hour each way taking the backroads. Also did the Waltham to Burlington route (slightly less distance, but using 95 for travel)... two hours each way during rush hour.
Just be aware what you're getting into...
Dan - Owner