The typical asking rate per listing is in the $20's per square foot per year. The Charleston region is going through a an increase in rates. In the last 3 months, the median rate rose $29 per sqft per year.
In the last 90 days, 133 listings have been posted online, so you'll want to check back regularly for new listings. About 41% of the available space in the Charleston are subleases, so you might be able to find a shorter term or below market rent. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
Even though the median size is 3,000 sqft, there are still 0 new availabilities below 2,000 sqft. Most buildings in this area are close to 2 floors. Most buildings in this area were built in 1986 and are Class A.