Here are some suggestions, but if you've found an even better deal -- please post it!
- Stay at a cute New England B'n'B like The Irving.
- Another B and B a short ride away on the red line, The John Jeffries House is at the Charles MGH stop.
- Harvard Square Hotel is very close and economical for a Harvard Square hotel. ($179 plus tax of 12.45% per night)
- The Charles Hotel is even a smidge closer and has valet parking.
- The Hyatt Regency is a short ride away on the number 1 bus and costs $90ish per night.
- Directory of local residents renting affordable rooms by the night.
These are about 5km from the conference venue, but have prices of $50 or less.
Other hostels a little further out can be found at HostelWorld.com.