On average, listings lease in the $10's per square foot per year. The Iowa region is going through a decline in rates. In the last 3 months, the median rate decreased $1 per sqft per year. That's a 4% decline in rent.
In the last 90 days, 499 listings have been posted online, so you'll want to check back regularly for new listings. About 2% of the available space in the Iowa 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,400 sqft. Most buildings in this area are close to 2 floors. Most buildings in this market were built in 1984 and are Class A.