Most listings are in the $10's per square foot per year. The Green Bay submarket is experiencing a a boost in rates. In the last 3 months, the median rate went up $16 per sqft per year.
In the last 90 days, 17 listings have been posted online, which means listings most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 18% of the office spaces in the Green Bay are subleases, so you might be able to find a shorter term or below market rent. 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 1,000 sqft. Most buildings in this market are around 2 floors. Most buildings in this region were built in 1974 and are Class B.