On average, listings lease in the $20's per square foot per year. The Kenai region is going through a an increase in rates. In the last 3 months, the median rate went up $28 per sqft per year.
In the last 90 days, 2 listings have been made available, which means office spaces are probably going fast. You'll want to be prepared to make an offer immediately. About 750% of the available leases in the Kenai are subleases, so you might be able to find a shorter term or below market rent. 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 870 sqft. Most buildings in this market were built in 1993 and are Class A.