On average, listings lease in the $20's per square foot per year. The Cascades region is experiencing a a boost in rates. In the last 3 months, the median rate rose $3 per sqft per year. That's a 13% increase in rent.
Compared to the rest of the Washington D.C. market, the Cascades submarket has lower rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 3 listings have been posted online, which means 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 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 1,770 sqft. Most buildings in this area are close to 3 floors. Most buildings in this region were built in 2001 and are Class B.