The typical asking rate per listing is in the $20's per square foot per year. The Bull Run submarket is going through a a boost in rates. In the last 3 months, the median rate rose $1 per sqft per year. That's a 2% rise in rent.
Compared to the rest of the Washington D.C. market, the Bull Run region has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 36 listings have been made available, which means spaces might be 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 1,960 sqft. Most buildings in this region are close to 2 floors. Most buildings in this area were built in 1988 and are Class B.