var price = 0;
var addon_pets = 0;
var rate = {
  'DLX': 20,
  'CAT': 10
};

for (var i in app.confirmation){
  var room = app.confirmation[i];
  for (var j in room.pet_rooms){
    addon_pets += room.pet_rooms[j].pets.length - 1;
  }
  price += rate[room.code];
}
price += rate['CAT'] * addon_pets;

item.price = price;
item.c_price = item.c_price;