that's what i'm thinking, but only those plastic throw-away cups my kid gets at the nicer restaurants. remove the bottom after the transplant takes, and bury.
To get them to persevere through the winter, you will want to keep the pots or box from freezing solid. Depending on the size of the box, you can bury it up to the rim in the ground, or you can set it on the ground and cover the entire thing with mulch. If the box is affixed to the house or a deck or such, there's not much you can really do.