What is avg cost of an irrevocable trust to protect assets in NYS?

It's no easier to answer that question than it is to answer the question, "how much does it cost to fix a car?"  A trust is just a tool of the lawyer's trade, and every case must be addressed on its own merits to determine what are the client's goals and objectives, as well as any complexities applicable to the particular case.  Lawyers are (or certainly should be) in the counseling business, not the document selling business.