On average, listings lease in the $20's per square foot per year. The Bismarck region is going through a an increase in rates. In the last 3 months, the median rate increased $1 per sqft per year. That's a 7% rise in rent.
In the last 90 days, 19 listings have been posted online, which means leases are probably 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 1,790 sqft. Most properties in this region are around 3 stories. Most buildings in this area were built in 1987 and are Class A.