The typical asking rate per listing is in the $10's per square foot per year. The Yucaipa region is seeing a decline in rates. In the last 3 months, the median rate fell $6 per sqft per year. That's a 26% decrease in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Yucaipa region has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 8 listings have been listed, which means listings are probably going fast. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 780 sqft. Most buildings in this market were built in 2008 and are Class B.