The typical asking rate per listing is in the $20's per square foot per year. The Mount Prospect region is seeing a an increase in rates. In the last 3 months, the median rate went up $23 per sqft per year.
Compared to the rest of the Chicagoland market, the Mount Prospect region has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 35 listings have come on the market, which means new availabilities most likley are going fast. You'll want to be prepared to make an offer immediately. About 40% of the office spaces in the Mount Prospect 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 2,500 sqft. Most buildings in this area are approximately 1 stories. Most buildings in this area were built in 1986 and are Class A.