On average, listings lease in the $10's per square foot per year. The Martin County submarket is going through a a rise in rates. In the last 3 months, the median rate rose $1 per sqft per year. That's a 3% increase in rent.
In the last 90 days, 51 listings have come on the market, so you'll want to check back regularly for new listings. About 2% of the available leases in the Martin County 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,350 sqft. Most buildings in this area are close to 2 stories. Most buildings in this market were built in 1983 and are Class B.