The typical asking rate per listing is in the $10's per square foot per year. The Crystal Lake region is going through a a rise in rates. In the last 3 months, the median rate went up $17 per sqft per year.
Compared to the rest of the Chicagoland market, the Crystal Lake submarket has less expensive rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 31 listings have been listed, which means office spaces are probably going fast. You'll want to be prepared to make an offer immediately. About 100% of the listings in the Crystal Lake 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,550 sqft. Most buildings in this area are approximately 1 floors. Most buildings in this market were built in 1996 and are Class A.