If you're looking for an inexpensive bed in Boston, Manuela's can't be beat. It's literally across the street from the subway, giving you easy access to the city, and a 25-minute walk to the convention center.
The house is definitely showing some age, but when it costs a quarter of anything else available in the area and you're only using it to bathe and sleep, it more than meets your needs.
Manuela is a very responsive and accommodating host as well. This was my second time staying with her and I'm sure I'll be going vack.