On average, listings lease in the $10's per square foot per year. The Northside submarket is going through a an increase in rates. In the last 3 months, the median rate increased $17 per sqft per year.
Compared to the rest of the Richmond market, the Northside region has lower rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 2 listings have come on the market, which means new availabilities most likley are going fast. You'll want to be prepared to make an offer immediately. 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 properties in this market are close to 1 floors. Most buildings in this market were built in 1954 and are Class B.
Not much of the real estate is used for commercial space, so it might be hard to find office space. Professional services is the dominant industry in this market. Most of the folk of Northside work from home. Commuting around 10 minutes a day is the norm for those who opt to reside in this part of town.