The typical asking rate per listing is in the $20's per square foot per year. The Gurnee submarket is going through a a rise in rates. In the last 3 months, the median rate increased $3 per sqft per year. That's a 14% increase in rent.
Compared to the rest of the Chicagoland market, the Gurnee region has lower rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 15 listings have been made available, which means new availabilities are probably 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 1,750 sqft. Most properties in this area are approximately 3 stories. Most buildings in this region were built in 1994 and are Class B.