Most listings are in the $20's per square foot per year. The Compton submarket is experiencing a a rise in rates. In the last 3 months, the median rate increased $6 per sqft per year. That's a 28% increase in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Compton submarket has less expensive rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 3 listings have been made available, which means new availabilities most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. 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 1,150 sqft. Most buildings in this area were built in 1980 and are Class B.