On average, listings lease in the $30's per square foot per year. The Rockville Centre submarket is going through a a rise in rates. In the last 3 months, the median rate rose $33 per sqft per year. That's a Inf% increase in rent.
In the last 90 days, 3 listings have been listed, which means office spaces might be 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 650 sqft. Most properties in this region are around 2 stories. Most buildings in this area were built in 1972 and are Class C.