On average, listings lease in the $20's per square foot per year. The Fauquier County submarket is going through a a boost in rates. In the last 3 months, the median rate went up $1 per sqft per year. That's a 7% rise in rent.
In the last 90 days, 4 listings have been listed, which means listings most likley are going fast. You'll want to be prepared to make an offer immediately. About 700% of the office spaces in the Fauquier County are subleases, so you might be able to find a shorter term or below market rent. 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 1,500 sqft. Most properties in this region are approximately 3 floors. Most buildings in this market were built in 1987 and are Class A.