Most listings are in the $30's per square foot per year. The Greater Portland submarket is going through a a rise in rates. In the last 3 months, the median rate went up $1 per sqft per year. That's a 4% increase in rent.
In the last 90 days, 506 listings have come on the market, so you'll want to check back regularly for new listings. About 5% of the office spaces in the Greater Portland are subleases, so you will probably have to focus your search on direct office leases. 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 2,340 sqft. Most buildings in this area are around 2 floors. Most buildings in this market were built in 1985 and are Class A.