Most listings are in the $10's per square foot per year. The Des Moines region is seeing a a rise in rates. In the last 3 months, the median rate increased $16 per sqft per year.
Compared to the rest of the Seattle Metropolitan Area market, the Des Moines submarket has lower rates, so you should have no trouble finding a great deal in this discounted submarket.
In the last 90 days, 2 listings have come on the market, which means new listings are probably going fast. You'll want to be prepared to make an offer immediately. About 150% of the available leases in the Des Moines are subleases, so you might be able to snag a great spot on a short term. 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 1,670 sqft. Most properties in this area are close to 2 floors. Most buildings in this region were built in 1984 and are Class B.