Can a "coon tail" in your hair be done at a salon or is it just an extension?

Im planning on getting my hair done next week and am thinking about adding a coon tail. Would the salon know what Im talking about and be able to permanently add it to my hair or is it just an extension? And how much do you think they would charge for it? Im getting a full foil already and a cut, and wondering how much the coon tail would add to that. Thanks!!