The typical asking rate per listing is in the $10's per square foot per year. The Yucaipa submarket is experiencing a an increase in rates. In the last 3 months, the median rate went up $16 per sqft per year. That's a Inf% rise in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Yucaipa region has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 13 listings have come on the market, which means spaces are probably 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 930 sqft. Most buildings in this market were built in 2008 and are Class B.