Most listings are in the $10's per square foot per year. The South Dakota submarket is going through a a rise in rates. In the last 3 months, the median rate went up $1 per sqft per year. That's a 5% rise in rent.
In the last 90 days, 130 listings have come on the market, so you'll want to check back regularly for new listings. About 2% of the listings in the South Dakota are subleases, so you will probably need to sign a longer term lease with the landlord directly. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,960 sqft. Most properties in this area are close to 2 stories. Most buildings in this area were built in 1991 and are Class A.