Well, a cardboard box works. The place where I got my worms lines a small cardboard box with several layers of newspaper and then puts some worms/bedding into the box. Finally folding the newspaper over the top and sealing up the box. Carefull about shipping your live worms accross the north in winter. They could freeze if sitting in a freezing location too long. I don't think putting them in a plastic container is such a good idea, cardboard is insulating and breathable and should survive priority mail shipping with worms. The cardboard can also be placed directly into the buyers worm bin.

hi there!
if you are doing craigslist and don't plan to ship the worms, you can do what the lower east side ecology center in nyc does. i picked up worms from them the other day, a whole LB. it was just a used milk container with the top opened, the worms, and some dirt (dunno the specifics of the dirt, looked like combo of regular castings and compost). i carried that thing around with me all day after i picked it up (errands) and even waited about 24 hours before adding the worms to the bin. they were all fine! :)

I received my worms in a small grocery bag in a cardboard box through the mail. The grocery bag was 2 heavy duty bags put together and stapled and then set down into a small cardboard box. Seemed to work well. I opened the top, tore a hole in the bottom and set the entire thing (bag/worms/bedding) in my bin....continuing to tear the bag a little every day. Worked! =o)