Most listings are in the $10's per square foot per year. The Iowa City region is going through a a rise in rates. In the last 3 months, the median rate increased $1 per sqft per year. That's a 8% rise in rent.
In the last 90 days, 24 listings have been listed, which means new availabilities might be leasing quickly. You'll want to be prepared to make an offer immediately. About 4% of the office spaces in the Iowa City are subleases, so you will probably have to consider a longer term lease. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,300 sqft. Most buildings in this area are close to 2 stories. Most buildings in this market were built in 1985 and are Class A.