On average, listings lease in the $20's per square foot per year. The Manassas Park region is experiencing a a rise in rates. In the last 3 months, the median rate went up $23 per sqft per year.
Compared to the rest of the Washington D.C. market, the Manassas Park submarket has less expensive rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 12 listings have come on the market, which means new availabilities most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. 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.