On average, listings lease in the $30's per square foot per year. The San Bernardino submarket is going through a a boost in rates. In the last 3 months, the median rate rose $9 per sqft per year. That's a 41% increase in rent.
Compared to the rest of the Metropolitan Los Angeles market, the San Bernardino submarket has less expensive rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 36 listings have been posted online, which means office spaces 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.
Even though the median size is 4,410 sqft, there are still 0 leases below 2,000 sqft. Most properties in this area are close to 2 floors. Most buildings in this market were built in 1984 and are Class B.