On average, listings lease in the $10's per square foot per year. The Roanoke region is going through a a boost in rates. In the last 3 months, the median rate increased $2 per sqft per year. That's a 9% increase in rent.
In the last 90 days, 26 listings have been made available, which means office spaces 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 on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,500 sqft. Most buildings in this area are approximately 2 stories. Most buildings in this market were built in 1953 and are Class B.