On average, listings lease in the $10's per square foot per year. The La Porte region is going through a an increase in rates. In the last 3 months, the median rate went up $16 per sqft per year.
In the last 90 days, 5 listings have come on the market, which means new listings 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 1,000 sqft. Most buildings in this market are around 2 floors. Most buildings in this region were built in 1914 and are Class B.