Most listings are in the $10's per square foot per year. The Dayton region is going through a decrease in rates. In the last 3 months, the median rate decreased $9 per sqft per year. That's a 36% decrease in rent.
In the last 90 days, 25 listings have come on the market, which means spaces most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 260% of the available leases in the Dayton 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 available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,240 sqft. Most properties in this area are approximately 2 stories. Most buildings in this region were built in 1971 and are Class B.