The typical asking rate per listing is in the $20's per square foot per year. The Ashburn region is experiencing a an increase in rates. In the last 3 months, the median rate went up $28 per sqft per year.
Compared to the rest of the Washington D.C. market, the Ashburn submarket has less expensive rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 8 listings have been posted online, which means new availabilities are probably going fast. You'll want to be prepared to make an offer immediately. About 388% of the office spaces in the Ashburn are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 2,260 sqft. Most buildings in this region are close to 2 stories. Most buildings in this market were built in 2002 and are Class A.