On average, listings lease in the $20's per square foot per year. The La Verne region is going through a a boost in rates. In the last 3 months, the median rate rose $24 per sqft per year.
Compared to the rest of the Metropolitan Los Angeles market, the La Verne submarket has lower rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 2 listings have been posted online, which means spaces are probably leasing quickly. You'll want to be prepared to make an offer immediately. 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 2,000 sqft. Most properties in this market are close to 2 stories. Most buildings in this area were built in 1994 and are Class B.