Most listings are in the $10's per square foot per year. The Green Bay submarket is seeing a a rise in rates. In the last 3 months, the median rate increased $3 per sqft per year. That's a 17% rise in rent.
In the last 90 days, 17 listings have been posted online, which means office spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 18% of the listings in the Green Bay 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 posted, 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 2 stories. Most buildings in this market were built in 1974 and are Class B.