I live on LI and no, it is NOT a NYS requirement. However, by taking the course, you can reduce the cost of one part of your insurance. Mine is not a percentage, but a dollar amount and even though it's small, every bit helps. It's good for three years. It also reduces some points on your license if you have accumulated those from tickets (ex. - moving violations like speeding). Thankfully, I don't have that problem.
I'm a member of AAA, so I take it through them. To the OP, check around to see if some insurance companies are offering it. I've never taken it for free, but I have taken it at a discounted price. I do the course in person and have had the same instructor for many years. He's a retired teacher and knows how to keep his audience interested in what has to be covered. He includes a lot of anecdotes about different driving-related incidents which makes the whole experience bearable.