Most listings are in the $10's per square foot per year. The Punta Gorda region is going through a a boost in rates. In the last 3 months, the median rate went up $16 per sqft per year.
In the last 90 days, 8 listings have been posted online, which means leases most likley are leasing quickly. You'll want to be prepared to make an offer immediately. 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 1,610 sqft. Most properties in this region are approximately 1 floors. Most buildings in this region were built in 1990 and are Class B.