Most listings are in the $50's per square foot per year. The Arlington County region is going through a an increase in rates. In the last 3 months, the median rate went up $3 per sqft per year. That's a 6% rise in rent.
In the last 90 days, 42 listings have come on the market, so you'll want to check back regularly for new listings. About 2% of the available space in the Arlington County 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.
Even though the median size is 11,270 sqft, there are still 0 leases below 2,000 sqft. Most buildings in this region are approximately 11 floors. Most buildings in this area were built in 1986 and are Class A.