Most listings are in the $10's per square foot per year. The Pleasant Prairie region is going through a a boost in rates. In the last 3 months, the median rate increased $17 per sqft per year.
Compared to the rest of the Chicagoland market, the Pleasant Prairie region has less expensive rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 6 listings have been made available, which means listings 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 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 1,350 sqft. Most buildings in this market were built in 1995 and are Class B.