The typical asking rate per listing is in the $20's per square foot per year. The Delaware region is going through a an increase in rates. In the last 3 months, the median rate increased $22 per sqft per year.
In the last 90 days, 2 listings have been listed, which means spaces most likley are going fast. You'll want to be prepared to make an offer immediately. About 200% of the office spaces in the Delaware 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,390 sqft. Most buildings in this region are around 2 floors. Most buildings in this region were built in 1964 and are Class C.