On average, listings lease in the $30's per square foot per year. The Bellflower region is going through a an increase in rates. In the last 3 months, the median rate went up $16 per sqft per year. That's a 80% increase in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Bellflower submarket has less expensive rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 4 listings have been listed, which means new availabilities might be going fast. You'll want to be prepared to make an offer immediately. About 125% of the listings in the Bellflower are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 1,260 sqft. Most properties in this area are approximately 2 stories. Most buildings in this region were built in 1954 and are Class B.