Most listings are in the $10's per square foot per year. The Mount Prospect region is going through a decrease in rates. In the last 3 months, the median rate decreased $7 per sqft per year. That's a 28% decrease in rent.
Compared to the rest of the Chicagoland market, the Mount Prospect submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 21 listings have been listed, which means office spaces most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. 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 1,370 sqft. Most properties in this area are approximately 4 stories. Most buildings in this market were built in 1986 and are Class B.