Most listings are in the $20's per square foot per year. The Manassas Park region is going through a decrease in rates. In the last 3 months, the median rate decreased $6 per sqft per year. That's a 21% decrease in rent.
Compared to the rest of the Washington D.C. market, the Manassas Park submarket has lower rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 12 listings have come on the market, which means new listings most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 33% of the available space in the Manassas Park 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 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 1,550 sqft. Most buildings in this market were built in 1983 and are Class A.