Most listings are in the $10's per square foot per year. The Smithfield region is going through a an increase in rates. In the last 3 months, the median rate increased $18 per sqft per year.
Compared to the rest of the The Triangle market, the Smithfield region has less expensive rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 6 listings have been made available, which means new listings might be going fast. 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 170 sqft. Most buildings in this area are close to 1 floors. Most buildings in this region were built in 1995 and are Class B.