Most listings are in the $30's per square foot per year. The Riverside region is experiencing a decrease in rates. In the last 3 months, the median rate fell $1 per sqft per year. That's a 2% decrease in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Riverside region has less expensive rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 61 listings have been posted online, so you'll want to check back regularly for new listings. 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 2,000 sqft. Most buildings in this market are around 2 stories. Most buildings in this market were built in 1989 and are Class C.