On average, listings lease in the $20's per square foot per year. The Greater Boston region is going through a a boost in rates. In the last 3 months, the median rate increased $0 per sqft per year. That's a 1% increase in rent.
In the last 90 days, 3593 listings have come on the market, so you'll want to check back regularly for new listings. About 1% of the available leases in the Greater Boston are subleases, so you will probably need to consider the implications of signing a direct lease with the building. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,090 sqft. Most buildings in this region are close to 2 stories. Most buildings in this area were built in 1969 and are Class A.