Most listings are in the $30's per square foot per year. The Hempstead region is going through a a boost in rates. In the last 3 months, the median rate increased $36 per sqft per year.
In the last 90 days, 2 listings have come on the market, which means new availabilities most likley are leasing quickly. You'll want to be prepared to make an offer immediately. 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 700 sqft. Most buildings in this market are close to 4 stories. Most buildings in this region were built in 1960 and are Class B.