The typical asking rate per listing is in the $0's per square foot per year. The Montclair submarket is seeing a decrease in rates. In the last 3 months, the median rate fell $46 per sqft per year. That's a 100% decline in rent.
In the last 90 days, 1 listings have been listed, which means leases most likley are going fast. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,300 sqft. Most buildings in this region were built in 1979 and are Class B.