The typical asking rate per listing is in the $30's per square foot per year. The El Cajon submarket is going through a a boost in rates. In the last 3 months, the median rate went up $13 per sqft per year. That's a 74% increase in rent.
Compared to the rest of the San Diego market, the El Cajon submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 16 listings have been listed, which means spaces are probably leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 75% of the office spaces in the El Cajon are subleases, so you might be able to snag a great spot on a short term. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,490 sqft. Most properties in this region are approximately 2 floors. Most buildings in this area were built in 1977 and are Class C.