The typical asking rate per listing is in the $10's per square foot per year. The New Castle region is seeing a a boost in rates. In the last 3 months, the median rate went up $15 per sqft per year.
In the last 90 days, 0 listings have come on the market, which means leases most likley are going fast. You'll want to be prepared to make an offer immediately. About Inf% of the office spaces in the New Castle are subleases, so you might be able to find a shorter term or below market rent. 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 1,160 sqft. Most properties in this area are close to 1 floors. Most buildings in this market were built in 1900 and are Class A.