On average, listings lease in the $20's per square foot per year. The Corona region is seeing a decline in rates. In the last 3 months, the median rate decreased $4 per sqft per year. That's a 14% decline in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Corona region has lower rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 57 listings have been made available, so you'll want to check back regularly for new listings. About 2% of the listings in the Corona are subleases, so you will probably have to focus your search on direct office leases. 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 1,960 sqft. Most properties in this area are approximately 2 stories. Most buildings in this region were built in 2005 and are Class A.