The typical asking rate per listing is 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 went up $2 per sqft per year. That's a 10% rise in rent.
In the last 90 days, 75 listings have come on the market, so you'll want to check back regularly for new listings. About 1% of the available leases in the Madison are subleases, so you will probably have to consider a longer term 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 2,370 sqft. Most properties in this market are around 2 floors. Most buildings in this region were built in 1987 and are Class B.