The typical asking rate per listing is in the $20's per square foot per year. The Towson region is going through a an increase in rates. In the last 3 months, the median rate went up $28 per sqft per year.
Compared to the rest of the Greater Baltimore market, the Towson submarket has smaller rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 38 listings have been made available, which means listings most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 76% of the available leases in the Towson are subleases, so you might be able to snag a great spot on a short term. 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 2,000 sqft. Most buildings in this market are close to 4 stories. Most buildings in this area were built in 1977 and are Class B.