Most listings are in the $20's per square foot per year. The Castle Hills submarket is experiencing a an increase in rates. In the last 3 months, the median rate rose $13 per sqft per year. That's a 73% increase in rent.
Compared to the rest of the Greater Austin market, the Castle Hills region has smaller rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 19 listings have been listed, which means new availabilities are probably leasing quickly. You'll want to be prepared to make an offer immediately. About 47% of the office spaces in the Castle Hills are subleases, so you might be able to sign a shorter term by taking over a previous lease. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 3,810 sqft, there are still 0 listings below 2,000 sqft. Most properties in this area are around 4 floors. Most buildings in this area were built in 1982 and are Class B.