The typical asking rate per listing is in the $20's per square foot per year. The Glendora region is experiencing 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 Glendora region has smaller rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 7 listings have come on the market, which means listings are probably going fast. You'll want to be prepared to make an offer immediately. About 157% of the listings in the Glendora are subleases, so you might be able to find a shorter term or below market rent. 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 1,500 sqft. Most buildings in this area are approximately 2 stories. Most buildings in this area were built in 1985 and are Class B.