The typical asking rate per listing is in the $10's per square foot per year. The Mendocino submarket is experiencing a an increase in rates. In the last 3 months, the median rate went up $19 per sqft per year.
In the last 90 days, 3 listings have been listed, which means leases most likley are leasing quickly. You'll want to be prepared to make an offer immediately. 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 1,550 sqft. Most properties in this region are around 1 floors. Most buildings in this area were built in 1988.