On average, listings lease in the $10's per square foot per year. The Yellowstone County region is going through a a boost in rates. In the last 3 months, the median rate increased $3 per sqft per year. That's a 16% rise in rent.
In the last 90 days, 19 listings have been posted online, which means listings most likley are 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,450 sqft. Most properties in this area are approximately 2 stories. Most buildings in this region were built in 1984 and are Class A.