Why not aluminum cans? There's still some plastic in there, but you can mostly recycle them, they must be fairly cheap, and they're quite light. As an added benefit they stack higher in transit with less extra packaging, at least if they're shipped like beer.

I literally just saw those for the first time. As I understand it they’re still plastic lined and the energy efficiency depends on how much recycling takes place. It depends if eliminating plastics is what you really care about or not.