On average, listings lease in the $10's per square foot per year. The Nampa region is experiencing a decline in rates. In the last 3 months, the median rate decreased $3 per sqft per year. That's a 13% decline in rent.
In the last 90 days, 22 listings have been listed, which means office spaces most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 5% of the listings in the Nampa are subleases, so you will probably have to focus your search on direct office leases. 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 870 sqft. Most buildings in this market are around 1 stories. Most buildings in this region were built in 2007 and are Class A.