On average, listings lease in the $10's per square foot per year. The Manchester region is going through a decrease in rates. In the last 3 months, the median rate fell $2 per sqft per year. That's a 11% decrease in rent.
In the last 90 days, 6 listings have been made available, which means listings most likley are going fast. You'll want to be prepared to make an offer immediately. 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 950 sqft. Most buildings in this market are approximately 2 floors. Most buildings in this area were built in 1939.