On average, listings lease in the $10's per square foot per year. The Oakland submarket is seeing a a boost in rates. In the last 3 months, the median rate went up $18 per sqft per year.
In the last 90 days, 1 listings have been made available, which means office spaces most likley are going fast. You'll want to be prepared to make an offer immediately. 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 2,110 sqft. Most buildings in this region are around 2 stories. Most buildings in this area were built in 1989 and are Class B.