The typical asking rate per listing is in the $20's per square foot per year. The St. Louis County region is going through a an increase in rates. In the last 3 months, the median rate went up $6 per sqft per year. That's a 31% increase in rent.
In the last 90 days, 89 listings have come on the market, so you'll want to check back regularly for new listings. About 1% of the available leases in the St. Louis County are subleases, so you will probably have to focus your search on direct office leases. 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 3,980 sqft, there are still 0 leases below 2,000 sqft. Most buildings in this market are approximately 3 floors. Most buildings in this area were built in 1964 and are Class B.