Most listings are in the $10's per square foot per year. The Alexandria submarket is seeing a decline in rates. In the last 3 months, the median rate fell $1 per sqft per year. That's a 7% decrease in rent.
In the last 90 days, 6 listings have been posted online, which means new availabilities most likley are leasing quickly. You'll want to be prepared to make an offer immediately. 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 2,160 sqft. Most properties in this area are around 1 floors. Most buildings in this area were built in 0 and are Class B.