The typical asking rate per listing is in the $10's per square foot per year. The Keller region is experiencing a decline in rates. In the last 3 months, the median rate decreased $3 per sqft per year. That's a 13% decrease in rent.
Compared to the rest of the DFW Metroplex market, the Keller submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 3 listings have been listed, which means listings are probably going fast. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,070 sqft. Most buildings in this market are close to 1 floors. Most buildings in this area were built in 2006 and are Class B.