Most listings are in the $20's per square foot per year. The Beavercreek region is going through a an increase in rates. In the last 3 months, the median rate increased $2 per sqft per year. That's a 10% increase in rent.
In the last 90 days, 14 listings have been posted online, which means new listings most likley are going fast. You'll want to be prepared to make an offer immediately. 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 2,000 sqft. Most buildings in this market are approximately 2 stories. Most buildings in this region were built in 1989 and are Class B.