Most listings are in the $30's per square foot per year. The Oceanside submarket is going through a a rise in rates. In the last 3 months, the median rate went up $9 per sqft per year. That's a 39% increase in rent.
Compared to the rest of the San Diego market, the Oceanside submarket has lower rates, so you should have no trouble finding a great deal in this undervalued submarket.
In the last 90 days, 60 listings have been posted online, so you'll want to check back regularly for new listings. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,360 sqft. Most buildings in this region are around 2 floors. Most buildings in this region were built in 1984 and are Class B.