Most listings are in the $20's per square foot per year. The Durham region is seeing a a rise in rates. In the last 3 months, the median rate rose $1 per sqft per year. That's a 3% rise in rent.
Compared to the rest of the The Triangle market, the Durham region has lower rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 76 listings have been listed, so you'll want to check back regularly for new listings. About 5% of the available space in the Durham are subleases, so you will probably need to sign a longer term lease with the landlord directly. 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 1,930 sqft. Most properties in this market are around 2 floors. Most buildings in this region were built in 1995 and are Class A.