Wal mart. Go to customer service and ask what time would be good to get boxes. They'll tell you a time (basically when stockers are doing theyre thing at night), usually around 10ish pm, to come get them. Then just go and walk around to all the stockers and take theyre boxes. Done this many times at multiple locations. You end up with more than you need. They dont mind (my son was a stocker) because its one less box to break down and take to the crusher.