The typical asking rate per listing is in the $10's per square foot per year. The Nassau County region is going through a decline in rates. In the last 3 months, the median rate decreased $3 per sqft per year. That's a 14% decline in rent.
In the last 90 days, 8 listings have come on the market, which means listings are probably leasing quickly. You'll want to be prepared to make an offer immediately. About 75% of the available leases in the Nassau County 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,560 sqft. Most properties in this market are approximately 2 stories. Most buildings in this market were built in 2000 and are Class A.