The typical asking rate per listing is in the $10's per square foot per year. The South Portland submarket is experiencing a decline in rates. In the last 3 months, the median rate fell $3 per sqft per year. That's a 13% decline in rent.
In the last 90 days, 18 listings have come on the market, which means new availabilities most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 17% of the listings in the South Portland are subleases, so you might be able to snag a great spot on a short term. 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 2,170 sqft. Most buildings in this area are approximately 2 floors. Most buildings in this region were built in 1974 and are Class A.