Compared to the rest of the Seattle Metropolitan Area market, the Des Moines submarket has smaller rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 6 listings have been made available, which means office spaces most likley are going fast. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,740 sqft. Most properties in this area are approximately 2 floors. Most buildings in this market were built in 1962 and are Class B.