Most listings are in the $20's per square foot per year. The Rancho Cucamonga region is going through a decline in rates. In the last 3 months, the median rate decreased $2 per sqft per year. That's a 6% decline in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Rancho Cucamonga region has smaller rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 36 listings have come on the market, which means leases most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 3% of the available leases in the Rancho Cucamonga 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.
Even though the median size is 3,350 sqft, there are still 0 listings below 2,000 sqft. Most buildings in this region are close to 2 floors. Most buildings in this area were built in 1991 and are Class B.