Most listings are in the $10's per square foot per year. The Nampa submarket is experiencing a decrease in rates. In the last 3 months, the median rate decreased $3 per sqft per year. That's a 12% decrease in rent.
In the last 90 days, 35 listings have been made available, which means new availabilities are probably leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 3% of the available leases in the Nampa 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 1,750 sqft. Most properties in this region are around 1 stories. Most buildings in this area were built in 2002 and are Class A.