The typical asking rate per listing is in the $20's per square foot per year. The Corpus Christi region is going through a an increase in rates. In the last 3 months, the median rate went up $2 per sqft per year. That's a 12% increase in rent.
In the last 90 days, 14 listings have been listed, which means spaces most likley are going fast. You'll want to be prepared to make an offer immediately. 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 1,900 sqft. Most buildings in this region are approximately 2 stories. Most buildings in this market were built in 1985 and are Class B.