The typical asking rate per listing is in the $20's per square foot per year. The Maryland Heights submarket is going through a a rise in rates. In the last 3 months, the median rate went up $1 per sqft per year. That's a 6% increase in rent.
In the last 90 days, 40 listings have been posted online, which means leases are probably leasing quickly. You'll want to be prepared to make an offer immediately. About 10% of the office spaces in the Maryland Heights are subleases, so you will probably need to sign a longer term lease with the landlord directly. 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 3,550 sqft, there are still 0 leases below 2,000 sqft. Most buildings in this area are approximately 2 stories. Most buildings in this market were built in 1984 and are Class B.