Most listings are in the $30's per square foot per year. The El Cajon submarket is going through a an increase in rates. In the last 3 months, the median rate increased $13 per sqft per year. That's a 74% increase in rent.
Compared to the rest of the San Diego market, the El Cajon region has smaller rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 16 listings have been made available, which means new listings might be going fast. You'll want to be prepared to make an offer immediately. About 69% of the office spaces in the El Cajon 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 available, 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 buildings in this area are approximately 2 floors. Most buildings in this region were built in 1977 and are Class C.