Most listings are in the $0's per square foot per year. The Oak Forest submarket is going through a decline in rates. In the last 3 months, the median rate decreased $18 per sqft per year. That's a 100% decline in rent.
In the last 90 days, 5 listings have been made available, which means leases 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 sqft. Most buildings in this market are around 1 stories. Most buildings in this area were built in 1971 and are Class B.