The typical asking rate per listing is in the $10's per square foot per year. The Affton submarket is experiencing a an increase in rates. In the last 3 months, the median rate increased $17 per sqft per year.
In the last 90 days, 1 listings have been listed, which means new availabilities might be going fast. You'll want to be prepared to make an offer immediately. 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 1,300 sqft. Most buildings in this area are approximately 1 stories. Most buildings in this area were built in 2001 and are Class B.