On average, listings lease in the $20's per square foot per year. The Ann Arbor submarket is going through a a rise in rates. In the last 3 months, the median rate rose $26 per sqft per year.
In the last 90 days, 52 listings have been posted online, so you'll want to check back regularly for new listings. About 60% of the listings in the Ann Arbor 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 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 2,250 sqft. Most buildings in this market are approximately 2 floors. Most buildings in this region were built in 1964 and are Class B.