On average, listings lease in the $10's per square foot per year. The Guilford Center submarket is seeing a a boost in rates. In the last 3 months, the median rate increased $16 per sqft per year.
In the last 90 days, 6 listings have been posted online, which means spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 200% of the listings in the Guilford Center 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 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 730 sqft. Most properties in this market are approximately 2 stories. Most buildings in this market were built in 1988 and are Class B.