Most listings are in the $10's per square foot per year. The Centereach submarket is going through a decrease in rates. In the last 3 months, the median rate fell $7 per sqft per year. That's a 29% decrease in rent.
In the last 90 days, 1 listings have been listed, which means office spaces are probably leasing quickly. You'll want to be prepared to make an offer immediately. 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 1,000 sqft. Most buildings in this market are around 1 floors. Most buildings in this market were built in 2001 and are Class B.