Most listings are in the $10's per square foot per year. The Wheeling submarket is going through a an increase in rates. In the last 3 months, the median rate went up $20 per sqft per year.
Compared to the rest of the Chicagoland market, the Wheeling submarket has smaller rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 4 listings have been listed, which means office spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 175% of the available leases in the Wheeling are subleases, so you might be able to snag a great spot on a short term. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,990 sqft. Most buildings in this market are approximately 1 stories. Most buildings in this market were built in 1982 and are Class B.