Most listings are in the $10's per square foot per year. The Clarksburg submarket is experiencing a a boost in rates. In the last 3 months, the median rate increased $15 per sqft per year.
In the last 90 days, 0 listings have come on the market, which means spaces most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. About Inf% of the available space in the Clarksburg 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 240 sqft. Most buildings in this area were built in 1998 and are Class B.