if($_POST["1"] == ("yes" || "Yes" || "YES" || "yEs" || "yeS" || "YEs" || "yES")) 
{
  setcookie("tos", "true", 0);
  header("Location: index.php?page=home");
  die();
}

if(($_COOKIE["tos"] == (null || "false")) || (!isset($_COOKIE["tos"]))) {
  setcookie("tos", "false", 0);
  if($_GET['page'] != 'tos') {
    header("Location: index.php?page=tos");
    die();
  }
}