Most listings are in the $30's per square foot per year. The Clayton region is going through a a boost in rates. In the last 3 months, the median rate went up $2 per sqft per year. That's a 5% rise in rent.
In the last 90 days, 39 listings have been made available, which means leases most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. About 10% of the office spaces in the Clayton are subleases, so you might be able to sign a shorter term by taking over a previous lease. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 3,600 sqft, there are still 0 leases below 2,000 sqft. Most buildings in this region are close to 14 floors. Most buildings in this area were built in 1968 and are Class A.