As above, when I posted out a load I had some self sealing bags, but they would only take 6 at a push and I ran out, so wrapped them in a bin bag then taped it all up in parcel tape, fairly cheap and effective, the pots are tough enough to withstand the postman's malhandling. Lump's suggestion might save you some packaging, but I doubt you'll make the buyer happyjust tape them together and wrap in brown paper, you can even but them in a black bag, fold it up, then cover it in tape