Most listings are in the $20's per square foot per year. The DFW Metroplex region is going through a a boost in rates. In the last 3 months, the median rate increased $0 per sqft per year. That's a 0% rise in rent.
In the last 90 days, 2745 listings have been made available, so you'll want to check back regularly for new listings. About 3% of the office spaces in the DFW Metroplex are subleases, so you will probably have to consider a longer term lease. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,970 sqft. Most buildings in this area are around 2 stories. Most buildings in this market were built in 1985 and are Class B.