The typical asking rate per listing is in the $20's per square foot per year. The West Chester region is seeing a an increase in rates. In the last 3 months, the median rate increased $4 per sqft per year. That's a 17% rise in rent.
In the last 90 days, 12 listings have been made available, which means new availabilities most likley are 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 1,500 sqft. Most buildings in this region are approximately 2 floors. Most buildings in this region were built in 1936 and are Class A.