On average, listings lease in the $10's per square foot per year. The Kennebunk submarket is going through a an increase in rates. In the last 3 months, the median rate increased $3 per sqft per year. That's a 17% rise in rent.
In the last 90 days, 9 listings have come on the market, which means new listings most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,290 sqft. Most buildings in this market are around 2 stories. Most buildings in this area were built in 1890 and are Class B.