The typical asking rate per listing is in the $10's per square foot per year. The Rexburg submarket is seeing a decline in rates. In the last 3 months, the median rate fell $1 per sqft per year. That's a 8% decrease in rent.
In the last 90 days, 5 listings have been posted online, which means office spaces might be leasing quickly. 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 area were built in 2006 and are Class C.