Most listings are in the $10's per square foot per year. The Manassas region is going through a decline in rates. In the last 3 months, the median rate decreased $4 per sqft per year. That's a 19% decline in rent.
Compared to the rest of the Washington D.C. market, the Manassas submarket has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 29 listings have been made available, which means new listings might be leasing quickly. You'll want to be prepared to make an offer immediately. About 31% of the available space in the Manassas 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,090 sqft. Most properties in this area are close to 2 floors. Most buildings in this market were built in 1989 and are Class B.