On average, listings lease in the $30's per square foot per year. The Manhattan region is going through a an increase in rates. In the last 3 months, the median rate rose $38 per sqft per year.
In the last 90 days, 10 listings have been listed, which means new availabilities are probably going fast. You'll want to be prepared to make an offer immediately. About 50% of the available space in the Manhattan are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 1,270 sqft. Most properties in this region are approximately 1 floors. Most buildings in this region were built in 1984 and are Class A.