Compared to the rest of the Washington D.C. market, the Fredericksburg region has less expensive rates, so you should have no trouble finding a great deal in this discounted submarket.
In the last 90 days, 28 listings have come on the market, which means spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 7% of the listings in the Fredericksburg are subleases, so you will probably have to consider a longer term lease. 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 1,070 sqft. Most buildings in this area are approximately 2 floors. Most buildings in this region were built in 1980 and are Class B.