Most listings are in the $20's per square foot per year. The Dallas County submarket is going through a decline in rates. In the last 3 months, the median rate decreased $1 per sqft per year. That's a 3% decline in rent.
In the last 90 days, 2432 listings have been listed, so you'll want to check back regularly for new listings. About 61% of the listings in the Dallas County are subleases, so you might be able to snag a great spot on a short term. 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 1,340 sqft. Most buildings in this area are close to 3 floors. Most buildings in this area were built in 1983 and are Class B.