The typical asking rate per listing is in the $10's per square foot per year. The San Bernardino region is going through a decrease in rates. In the last 3 months, the median rate decreased $8 per sqft per year. That's a 36% decline in rent.
Compared to the rest of the Metropolitan Los Angeles market, the San Bernardino submarket has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 78 listings have come on the market, so you'll want to check back regularly for new listings. About 5% of the listings in the San Bernardino are subleases, so you will probably need to sign a longer term lease with the landlord directly. 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 670 sqft. Most properties in this area are around 2 floors. Most buildings in this area were built in 1984 and are Class B.