Most listings are in the $30's per square foot per year. The Sebastopol region is experiencing a an increase in rates. In the last 3 months, the median rate went up $36 per sqft per year.
Compared to the rest of the Bay Area market, the Sebastopol submarket has lower rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 1 listings have come on the market, which means spaces might be leasing quickly. You'll want to be prepared to make an offer immediately. About 600% of the office spaces in the Sebastopol 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 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 1,900 sqft. Most buildings in this market are close to 2 floors. Most buildings in this area were built in 1991 and are Class B.