Most listings are in the $10's per square foot per year. The Des Moines County submarket is going through a a rise in rates. In the last 3 months, the median rate rose $13 per sqft per year.
In the last 90 days, 23 listings have been made available, which means listings most likley are leasing quickly. 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 2,500 sqft. Most buildings in this region are close to 1 floors. Most buildings in this region were built in 1975.