Most listings are in the $10's per square foot per year. The Johnson County submarket is experiencing a a rise in rates. In the last 3 months, the median rate rose $18 per sqft per year.
In the last 90 days, 12 listings have been made available, which means new availabilities most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 100% of the listings in the Johnson County are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 1,300 sqft. Most properties in this market are close to 1 stories. Most buildings in this area were built in 1978 and are Class B.