Most listings are in the $30's per square foot per year. The Oceanside region is experiencing a an increase in rates. In the last 3 months, the median rate increased $2 per sqft per year. That's a 5% increase in rent.
Compared to the rest of the San Diego market, the Oceanside submarket has less expensive rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 64 listings have come on the market, so you'll want to check back regularly for new listings. About 20% of the listings in the Oceanside 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 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 1,220 sqft. Most properties in this area are close to 2 stories. Most buildings in this market were built in 1987 and are Class B.