Most listings are in the $10's per square foot per year. The Bensenville submarket is going through a a rise in rates. In the last 3 months, the median rate rose $17 per sqft per year.
Compared to the rest of the Chicagoland market, the Bensenville region has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 10 listings have been made available, which means office spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 150% of the available space in the Bensenville are subleases, so you might be able to find a shorter term or below market rent. 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 1,590 sqft. Most properties in this market are around 1 floors. Most buildings in this market were built in 1979 and are Class A.