Most listings are in the $20's per square foot per year. The Madison region is experiencing a a rise in rates. In the last 3 months, the median rate rose $1 per sqft per year. That's a 3% increase in rent.
In the last 90 days, 57 listings have come on the market, so you'll want to check back regularly for new listings. About 5% of the available leases in the Madison are subleases, so you will probably need to sign a longer term lease with the landlord directly. 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 market are approximately 2 stories. Most buildings in this region were built in 1989 and are Class B.