I grow some of my herbs in those styrofoam ice chests with holes poked in them for drainage. They have lasted a long time. Now I'm thinking I could decorate them to make inexpensive "pots" as well.
The smaller ones are somewhere around $1 at various places. Even just flipped over plants to cover them when neeeded for insulation and protection would work well, if they are weighted down. Your ideas have sparked some ideas of my own. Thanks!