Most listings are in the $20's per square foot per year. The Glen Ellyn submarket is going through a a boost in rates. In the last 3 months, the median rate went up $22 per sqft per year.
Compared to the rest of the Chicagoland market, the Glen Ellyn region has smaller rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 5 listings have been listed, which means new availabilities most likley are going fast. 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.
Even though the median size is 4,090 sqft, there are still 0 spaces below 2,000 sqft. Most properties in this market are approximately 1 stories. Most buildings in this region were built in 1983 and are Class A.