Most listings are in the $10's per square foot per year. The Richmond submarket is going through a decrease in rates. In the last 3 months, the median rate decreased $13 per sqft per year. That's a 42% decline in rent.
Compared to the rest of the East Bay market, the Richmond region has smaller rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 10 listings have come on the market, which means new availabilities most likley are going fast. You'll want to be prepared to make an offer immediately. About 10% of the available space in the Richmond are subleases, so you will probably need to consider the implications of signing a direct lease with the building. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 9,390 sqft, there are still 0 leases below 2,000 sqft. Most properties in this area are around 1 floors. Most buildings in this area were built in 1978 and are Class A.