I did a roof for a friend's contracting firm on a third party's building. This work was part of his contract. Because he was a friend no formal contract was drawn up. He has been long paid for this job but keeps telling me times are tough he will get it to me when I can. He will won't.This happened about four years ago. Can I still collect this money and how? Where would I begin? I am an N.J. LLC so will I need an attorney?

So, you said there is no written contract? No proof will go nowhere.

No implied contract? He does acknowledge the debt and has made 1 - $500.00 payment.

Well make him put the debt he owes you into paperwork and then you will have something to work with.

... This happened about four years ago. Can I still collect this money and how? Where would I begin? I am an N.J. LLC so will I need an attorney?

You said three years in the title to this thread. No matter. Whether it's 3 or 4 years, the SOL is 6 years.

How much do you figure he owes you? Was this labor & materials, or just your labor? Did you give him an invoice?

If it's below the maximum amount for small claims actions, I woud sue him in small claims court. The fact that you are doing business as a LLC shouldn't matter. While a LLC is considered a partnership for tax purposes, actually a single-owner LLC is the same as a sole proprietorship for the purpose of capacity to sue. You can almost always represent yourself in court, and especially small claims court.