The typical asking rate per listing is in the $30's per square foot per year. The Mount Pleasant submarket is going through a an increase in rates. In the last 3 months, the median rate rose $4 per sqft per year. That's a 11% rise in rent.
In the last 90 days, 35 listings have been made available, which means office spaces most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 6% of the office spaces in the Mount Pleasant 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,000 sqft. Most buildings in this region are approximately 2 floors. Most buildings in this market were built in 2002 and are Class A.