On average, listings lease in the $30's per square foot per year. The Carnegie submarket is going through a an increase in rates. In the last 3 months, the median rate increased $32 per sqft per year.
In the last 90 days, 6 listings have been posted online, which means listings most likley are going fast. You'll want to be prepared to make an offer immediately. About 67% of the office spaces in the Carnegie are subleases, so you might be able to snag a great spot on a short term. 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 22,000 sqft, there are still 0 spaces below 2,000 sqft. Most properties in this market are around 2 stories. Most buildings in this area were built in 1985 and are Class B.