On average, listings lease in the $10's per square foot per year. The Mundelein submarket is going through a decline in rates. In the last 3 months, the median rate decreased $7 per sqft per year. That's a 30% decrease in rent.
Compared to the rest of the Chicagoland market, the Mundelein region has less expensive rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 8 listings have come on the market, which means listings most likley are leasing quickly. You'll want to be prepared to make an offer immediately. 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 2,440 sqft. Most buildings in this area are around 1 stories. Most buildings in this region were built in 1993 and are Class A.