Most listings are in the $10's per square foot per year. The Porter County region is going through a an increase in rates. In the last 3 months, the median rate increased $1 per sqft per year. That's a 4% rise in rent.
In the last 90 days, 22 listings have been listed, which means office spaces most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 5% of the office spaces in the Porter County are subleases, so you will probably need to consider the implications of signing a direct lease with the building. 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 1,300 sqft. Most buildings in this area are around 1 floors. Most buildings in this area were built in 1980 and are Class B.