Where should I get my Guinea Pig?

I am planning on getting a guinea pig. I do not know any animal shelters in my area that have guinea pigs. I have a large cage and money is not an issue aat all, but I do not know where to buy it. Is Petco really that bad? I do not want to go to a pet store but i do not know what to do. I live in Long Island, New York 11577. Please Help!!!